Ponisseril Somasundaran - US grants

Objectives and Relevancy: This project is for a cooperative research between Dr. P. Somasudaran of Columbia University and Drs. R. Mallikarjunan and S. Venkatachalam of the Indian Institute of Technology (IIT) at Bombay. The project is aimed towards understanding the mechanisms of a potential fine beneficiation technique, namely, electroflotation and developing it for beneficiation of selected problem ores. The expertise in IIT, Bombay in electrochemistry and flotation techniques complement that at Columbia University in surface and colloid chemical aspects of flotation of fines in the investigation. The study will include the electroflotation of selected oxides, salt type and sulfide minerals as a function of bubble size and size distribution charge produced, using different electrode designs, and studiesof forces of interaction of such bubbles with minerals. The U.S.-India program supports cooperative research between scientists of the two countries in areas of interest to NSF when benefit is expected to result from the collaboration This project falls in that category. Merit: The U.S. scientist is one of this country's top scientists in the field of materials and minerals processing. IIT Bombay is one of India's prestigious academic and research institutes. The research area deals with an important problem facing the mining industry in the U.S. and is also important to India. Funding: The project is being funded under two grants: The Indian Inst. of Tech. at Bombay: INT 87-16926 $57,143 in Indian currency Columbia University: INT 87-04303 $17,135 in Indian currency plus US$29,218

RESEARCH SUMMARY: Adsorption of surfactants from aqueous solution is an important but complex phenomenon due to the influence of factors including surfactant structure (functional groups, chain length, branching), solid mineralogy and morphological heterogeneity and solution properties. Absorption (loss) of surfactants is investigated here by studying their interactions with minerals, dissolved mineral species, polymers, oils and alcohols. In order to understand the absorption phenomenon, in the previous grant, other key properties such as zeta potential, wettability, CMC, mineral dissolution and surfactant chromatographic separation were monitored. It was shown that when soluble and semisoluble solids are present, there will be not only alterations of the solids due to surface precipitaiton but also depletion of surfactants due to bulk precipitation. A major process responsible for surfactant loss has been identified to be, in addition to electrostatic and hemimicellar absorption, surfactant precipitation particularly in solutions containing metal ions. It appears now that surfactants can be suitably modified to tolerate such hostile environments. Particular emphasis is being placed on ethoxylated surfactants since they can be manipulated to yield desired interfacial tension and salt tolerance. The PI has already obtained total inhibition of precipitaton with certain ethoxylated sulfonates in gypsum containing substrates which are normally very hostile to sulfonates. The role of structural modifications such as ethoxylation is not fully understood, but can be studied using a combination of techniques. It is the aim of the proposed work to investigate (using absorption, electrokinetic, chromatographic and spectroscopic techniques). The mechanisms by which structural modifications affect absorption/precipitation and to identify the reasons for the selective/preferential absorption or synergism observed in mixed systems of the above surfactants. UNIQUENESS AND INNOVATION: In contrast to other work on absorption, this research includes also the effects on absorption of dissolution of the solid and interaction of the dissolved species with the surfactant leading to complexation and even precipitation. Solids invariably dissolve and the dissolved species often govern the entire absorption (abstraction) behavior and yet these effects have been ignored in the past. In this research, the effect of dissolved species is being quantitatively determined and the absorption/desorption phenomenon and hysteresis phenomenon explained.

The PI proposes to develop efficient methods of processing iron and phosphate ores. The proposed work deals with the interfacial processes in iron oxide-silica system with the specific purpose of developing flocculants that can produce selective aggregation of component minerals. Topics such as adsorption of surfactants and polymers on mineral surfaces, electrokinetic studies under conditions similar to those encountered in actual seperation processes and possibilities for selective flocculation seperation between hematite and clays by flocculants with functional groups such as hydroxamates will be investigated.

The project addresses some of the factors limiting the current density of the new, high-temperature ceramic oxide superconducting materials. It is known that critical current density is much higher along the basal plane of the orthorhomlic structure of the YBa2Cu3O7- material than along the C-axis perpendicular to the basal plane. This project will investigate the effect of precursors, mixing and heat treatment, grinding and separation of superconducting ceramic oxide powder. Emphasis will be on developing schemes for separation of YBa2Cu3O7- powder based on its morphological, compositional and size differences. This may enable orientation of the grains of bulk material preferentially along the direction of current flow.

This award will support collaborative research between Professor Ponisseril Somasundaran of the Henry Krumb School of Mines, Columbia University, New York, and Dr. B. Cabane, Solid-State Physics Laboratory, University de Paris-Sud, France, on the subject of mechanisms of colloid formation and dispersion. Small angle neutron scattering (SANS) will be applied to the study of colloidal aggregates at the sub-micron size level, with the intent of determining dimensions and growth characteristics of aggregates, and on the thickness of submicronic adsorbed layers. By improving our understanding of the mechanism of colloidal dispersion, the development of a basic theory of colloidal aggregation may be brought closer to realization. The expertise of the U.S. and French groups is complementary. The U.S. group has considerable experience in the study of aggregate formation in mineral oxides, and in the solution chemistry of this and other systems; the French collaborator has considerable experience in SANS, and its application to polymer/micelle interactions. Through previous visits, the French collaborator is familiar with the equipment available in the U.S. researcher's laboratory. The proposed cooperation provides the U.S. researcher with an opportunity to use equipment and techniques for SANS not readily available to him in the U.S. This work could have important applications in such industrial processes as water treatment and mineral processing.

For a deeper understanding of the adsorption process in general and of the microstructure of the adsorbed phase in particular, this grant funds purchase of a spectrofluorometer capable of steady-state and time-resolved fluorescence measurements. The equipment is provided with double monochromators at the excitation and emission ends for optimum performance and has the facility to record corrected luminescence decay-time measurements. It was thyratron grated, flash lamp triggered nanosecond pulse to excite the luminescent samples. It can also measure time-resolved spectra. Surfactants and polymers adsorbed on a solid surface from solution modify surface properties drastically. Such phenomena have far reaching effects on the industrially and technologically important processes of flotation, flocculation, fine particle separation, oil recovery, and processing of electronic and ceramic green bodies. Earlier workers have focused on measurements such as adsorption density, zeta potentials, and contact angels. Recent efforts using fluorescence spectroscopy have demonstrated the potential of luminescence techniques to elucidate the structure and dynamics of evolution of the adsorbed layer in great detail. This award will significantly expand such work.

It is proposed to examine the effects of some promising structural variations on the adsorption of surfactants such as xylene sulfonates, ethoxylated sulfonates, and ethoxylated alcohols. Fluorescence, electron spin resonance, resonance Raman and NMR spectroscopy will be used to characterize the microstructure of the absorbed layers and calorimetry for fundamental thermodynamic information on the absorption of these surfactants. The adsorption of mixtures of these surfactants as well as mixtures with nonionic ethoxylated alcohols on solids will be investigated in detail using these techniques in conjunction with surface tension, electrokinetic and wettability measurements. This comprehensive approach should shed new light on interactions between surfactants during their absorption as well as self-association and orientation during packing at interfaces and help to identify optimum surfactant structure and system conditions for different processes.

This proposal addresses several basic issues of the colloidal stability in non-aqueous media: the effect of water content in the presence of a surfactant, modeling of flocculation induced by water, measurements on the stabilizing effect of surfactants, and the correlation between the green body microstructure and suspension stability. For this purpose, measurements of physicochemical properties, such as adsorption and zeta potential, will be performed. The molecular conformation at the solid-liquid interface will be investigated using Electron Spin Resonance and Nuclear Magnetic Resonance methods. The research has applications in ceramic and tape processing, inks, paints, and in other energy and environment related processes.*** //

The purchase of an Electron Spin Resonance Spectrometer is requested. The system will consist of a basic console, an analog recorder and display, appropriate microprocessor systems for the superheterodyne and field controller and data handling systems. It will be used to develop a full understanding of the process of adsorption of various surfactants an polymers and the effect of different parameters on the structure of the adsorbed layers. Adsorption of surfactants and polymers at the solid/liquid interface modify the surface properties of the solid. Such modifications are used in many industrial processes such as flocculation, enhanced oil recovery and flotation. In addition, the adsorbed layers, particularly self-assemblies such as hemimicelles have potential use in novel applications such as catalysis and isotope separation. Hence, understanding of the adsorption phenomena is of great importance. Earlier work focussed on understanding the physico-chemical mechanisms of adsorption of surfactants and polymers by measuring adsorption density, zeta potential, wettability and adsorption enthalpies. Such studies have helped in generating a mechanistic picture of the structure of the adsorbed layer. However, it has become clear that a molecular level understanding of adsorption is essential for the full utilization of it in various processes. Recently, EST has been used probe absorbed layers on solids on a molecular level. These studies have demonstrated the potential of ESR Spectroscopy to elucidate the mechanisms of formation of adsorbed layers and hence of adsorption. ESR spectroscopy is also the technique which recently proved very useful for us in examining the orientation of surfactants on solids in non-aqueous medium. Future research plans using the equipment will includes conformational changes of polymers with flocculation and dispersion of fines. Polymers labelled with nitroxide type probes will be used for such studies. Another important area of investigation is to elucidate the role of surfactant

Surfactant adsorption is an important phenomenon in many processes such as enhanced oil recovery, detergency, flotation, and molecular electronics and microstructure of the adsorbed layers a governing role in determining the efficiency of these processes. An approach combining advanced spectroscopic techniques such as luminescence, electron spin, resonance, Raman and NMR with conventional techniques of adsorption, electrokinetic, calorimetric and wettability has been used in recent studies to determine important microstructural properties such as micropolarity, microfluidity, aggregation number and surfactant and polymer orientation for several alumina-dodecyl sulfonate/polyacrylic acid systems for the first time. It is now possible to determine such properties in mixed surfactant systems that are invariably involved in practical systems. Mixed systems offer significant advantages in terms of high surface activity, salt tolerance, reduced precipitation loss etc. On the other hand, preferential adsorption from surfactant mixtures will cause chromatographic separation of the surfactant components resulting not only in loss of surfactants, but also in significant changes in the efficiency of the processes involved. Important questions to be answered include the effect of mixing, for example, anionics with nonionics, effect of relevant variables such as pH, ionic strength, multivalent ions concentration, temperature and order of addition of the components. It is most interesting to determine arrangement and rearrangement of the adsorbate species as the system is subjected to perturbations of composition, pH, etc. and to determine the resultant changes in the interfacial behavior of the systems. It is the aim of this work to investigate molecular level behavior of the species in mixed adsorbed films as a function of surfactant structure, PH, salinity, hardness, temperature using the comprehensive approach involving above spectroscopic and adsorption techniques. It will also be a major aim to model these systems with the help of additional information to be obtained from microcalorimetric investigation. Also, new techniques will be explored as in the past to determine additional micro and nano level properties of the adsorbed layers. With this multipronged approach, it should be possible to develop an accurate understanding of the adsorption mechanisms of real surfactant systems and to develop capability to control adsorption and to manipulate the configurational properties of the adsorbed species and their aggregates.

9311940 Somasundaran The stability of colloidal dispersions in non-aqueous media is a phenomenon of vital importance in a number of technologies such as ceramic and tape processing, inks and paints manufacture, oil recovery from tar sands and electrophoretic displays systems. However, major questions on the mechanisms of adsorption of stabilizers on colloidal particles and their stabilization remain largely unanswered. The complex solid- solvent-dispersant interactions that play a critical role in adsorption and subsequent stabilization are not well understood. Also, there is a lack of both fundamental information on the role of water and other polar impurities which have been identified to affect the suspension behavior markedly and on methods to counter the detrimental effects on these impurities. It becomes important to develop such information in order to further advance so many technologies that use processes involving non-aqueous media. Project addresses a multi-pronged approach combining the phenomenological description of suspension stability (settling rate, viscosity), the measurement of physico-chemical properties (adsorption, zeta potential, heats of adsorption) and the use of spectroscopic techniques (ESR, NMR, Fluorescence spectroscopy) to probe micro-structures in solution and at the interface. It focuses on some of the critical issues of adsorption and colloidal stability in non polar media. Specifically, the project investigates the role of the solid surface and the solvent on the adsorption of surfactants on particles from non- aqueous media. Also the role of surface charge and hydration in stabilizing dispersions, the effect of water and other polar impurities on charge development and conformation of the adsorbed molecules investigated. Stabilization effects of macromolecules and surfactant mixtures will be included in the study since they hold maximum practical potential. These studies coupled with the proposed novel spe ctroscopic investigation will enable the PI's to elucidate the fundamental mechanisms of adsorption and stabilization and also to provide guidelines for choosing the appropriate dispersant/solvent combinations and processing schemes to obtain optimum properties for a given non-aqueous dispersion. *** 9311940 Somasundaran The stability of colloidal dispersions in non-aqueous media is a phenomenon of vital importance in a number of technologies such as ceramic and tape processing, inks and paints manufacture, oil recovery from tar sands and electrophoretic displays systems. However, major questions on the mechanisms of adsorption of stabilizers on colloidal particles and their stabilization remain largely unanswered. The complex solid-solvent-dispersant interactions that play a critical role in adsorption and subsequent stabilization are not well understood. Also, there is a lack of both fundamental information on the role of water and other polar impurities which have been identified to affect the suspension behavior markedly and on methods to counter the detrimental effects on these impurities. It becomes important to develop such information in order to further advance so many technologies that use processes involving non-aqueous media. Project addresses a multi-pronged approach combining the phenomenological description of suspension stability (settling rate, viscosity), the measurement of physico-chemical properties (adsorption, zeta potential, heats of adsorption) and the use of spectroscopic techniques (ESR, NMR, Fluorescence spectroscopy) to probe micro-structures in solution and at the interface. It focuses on some of the critical issues of adsorption and colloidal stability in non polar media. Specifically, the project investigates the role of the solid surface and the solvent on the adsorption of surfactants on particles from non-aqueous media. Also the role of surface charge and hydration in stabilizing dispersions, the effect of water and other polar impurities on charge development and conformation of the adsorbed molecules investigated. Stabilization effects of macromolecules and surfactant mixtures will be included in the study since they hold maximum practical potential. These studies coupled with the proposed novel spectroscopic investigation will enable the PI's to elucidate the fundamental mechanisms of adsorption and stabilization and also to provide guidelines for choosing the appropriate dispersant/solvent combinations and processing schemes to obtain optimum properties for a given non-aqueous dispersion. ***

Somasundaran 9316228 SGER: Polymer/Surfactant and Protein/Lipid Interactions at Aqueous Interfaces This Small Grant for Exploratory Research (SGER) applies recently developed methods in air/water surface micromanometry to obtain the thermodynamic parameters for selected polymers and proteins referenced to near-ideal monolayer states at very low surface pressures and densities. These experiments should lead to the entropies and other thermodynamic functions for dense non-ideal conditions. The exploratory results will be used to adapt the surface micromanometry method to the measurement of interactions of polymers and proteins with surfactants. The results are expected to give information on polymer confirmations and the energetics of polymer-amphiphiles complexes at the fluid interfaces and to assist progress in several technologies, including the preparation of molecular assemblies on the nano scale, characterization and use of chiral complexes, aspects of the mechanisms of drug action related to membranes, wettability and foam and emulsion control. The grant provides for the transfer of equipment from British Petroleum ***

9415417 Somasundaran Description: This project supports collaboration between Dr. P. Somasundaran of the School of Mining at Columbia University and Dr. Pradip of the Tata Research, Development & Design Centre in Pune, India. An integrated approach is proposed to develop an accurate understanding of the mechanisms involved to alleviate the problems associated with separation of fines and ultrafines from raw materials. It is planned to investigate selective flocculation/dispersion of hematite- alumina system of fines and ultrafines in the presence of polymeric reagents. Emphasis will be on the identification of mechanisms by which interactions between reagents at the interface control selectivity. A multi-pronged approach using diffuse reflectance infra-red Fourier transform (DRIFT) spectroscopy, fluorescence spectroscopy, electron spin resonance spectroscopy along with conventional techniques of electrokinetics, adsorption, flocculation and wetting will be employed. Scope: The project brings together two well regarded laboratories in India and the U.S. to conduct research in an important area of mineral processing. The scientists have complementary capabilities and resources and also have excellent track record of research. Students from the two countries will be involved in the research. The project meets INT objectives for enhancing U.S.-foreign collaboration in areas of interest to both sides. ***

CTS-9510190 Pethica Columbia Univ. The potential of using cyclic lactams for separation of organics from aqueous solutions will be investigated. Preliminary data indicate that cyclic lactams from micelles, exhibit a lower consulate temperature (LCT) with water, and have substantial capacity to solubilize aromatics such as pyrene. The phase diagrams of alkyl-N-pyrrolidinone/water and partition coefficients will be measured for selected solutes. Similar studies will also focus on a liquid alkene-grafted polyvinyl pyrrolidinone that is water-insoluble and has low interfacial tension. Extraction of the solutes will be performed by changing temperature or by using mechanical dispersion of the liquid polymers followed by centrifugation. The research may lead to the development of low-toxicity, biodegradable and non-volatile solvents for the recovery of biochemical from fermentation broths and the removal of environmentally undesirable chemicals from aqueous solutions.

9523006 Somasundaran This award is for the implementation of a MS level educational and training program on pharmaceutical engineering in the Department of Chemical Engineering at Columbia University. It will provide tuition and stipend for three graduate students for three years. The pharmaceutical industry will provide similar support for additional seven students. This program is designed to meet the vital need of the pharmaceutical industry for engineers specially trained in modern processing and manufacturing techniques. Five new graduate level courses in different aspects of manufacturing of pharmaceuticals will be part of the curriculum. The curriculum will be developed with close cooperation between the Columbia University faculty and industrial partners. Adjunct faculty drawn from the pharmaceutical industry will participate in instruction and mentoring. A ten week industrial internship with faculty oversight will be a requirement. An advisory committee consisting of senior personnel from the pharmaceutical industry and academe will provide guidance and evaluation.

This three-year award for U.S.-France cooperative research in colloid and surface chemistry involves P. Somasundaran of Columbia University and Jerzy Mielczarski of the Institut National Polytechnique de Lorraine, France. The objective of the research is to investigate the interaction of adsorbed ions and molecules, especially, surfactants at solid surfaces. They will study the mechanisms involved in the interaction of different surfactants and organic pollutants with minerals, including fatty acids, alumina, calcite and aromatic pollutants. The project takes advantage of French expertise in calorimetry and in surface chemistry. The underlying science will contribute towards achieving an efficient and low cost means of removing toxic substances from water and other wastes.

Abstract Somasundaran, P./Columbia U. EEC-9708150 This award to the Columbia University is to study the feasibility of establishing an Industry/University Cooperative Research Center on the characterization and development of novel specialty surfactants for applications in chemical, pharmaceutical and biological consumer products. The Center will also emphasize on the development of knowledge base on the relationship between structure of different surfactants for specific industrial applications. The research program, structure and organization of the proposed Center will be studied in an industry/university workshop.

ABSTRACT CTS-9809053 Somasundaran, P. Columbia U. Surface modification of solids plays a vital role in many traditional and emerging industrial processes dependent upon interfacial phenomena such as adhesion, wetting, lubrication, electrodeposition, catalysis and aggregation/dispersion. Chemical modification by adsorption offers an excellent means to control interfacial behavior of colloidal systems. Past work on adsorption of surfactants and polymers on solid minerals has shown that interactions among these species leading to aggregation can have marked effects on interfacial behavior1. Using a multipronged approach combining traditional techniques of adsorption, wettability and lubrication with advanced spectroscopic techniques of fluorescence, electron spin resonance and resonance Raman, we have proposed ionic surfactants to adsorb individually at low concentrations and in clusters at high concentrations (hemimicelles, admicelles, solloids)2,3. Importantly, reorientation of adsorbed species has been proposed to occur under high concentrations. Such reorientation and reconformation can have drastic effects, for example, in wettability and adhesion inorganics) are introduced into the system. While fluorescence and electron. Reconformation can also occur when additives (surfactants, polymers and spin resonance techniques have yielded information on such microproperties as polarity, viscosity and aggregation number of the clusters on solids, direct investigation on a molecular scale in the concentration range where surface aggregates evolve has not yet been done. Studies conducted in the past have been carried out in the higher concentration ranges above critical micelle concentration4,5. A promising innovation allowing such investigation is the development of scanning probe microscopy (SPM). SPM is a generic name and at present it includes scanning tunneling microscopy and atomic force microscopy. Other SPM techniques under development are scanning ion, magnetic f orce, photon scanning and thermal profiler microscopy6. The three dimensional topography-mapping capabilities of SPM techniques at extremely high resolution (atomic scale) in vacuum, air, or liquid environments are unparalleled. The interaction force measurements in colloidal systems are important both from a theoretical and practical point of view. The interaction force between the SPM tip and the sample can yield information which so far has not been obtainable for dispersed systems. The proposed acquisition of the atomic force microscope will enable us to directly probe the adsorbed layer in-situ and changes in its structure due to chemical and hydrodynamic factors. This will markedly increase our investigative capability since the use of atomic force microscope concurrently with other techniques will enable us to develop an understanding of interfacial processes on a nanoscale. Such information also leads to engineering capability to manipulate and control modification of surfaces by adsorption for optimum effect.

ABSTRACT
EEC-9813309
Somasundaran/Columbia

This is an Exploratory Research Project to augment the Industry/University Cooperative Research Center
for Surfactants.

The dynamics of the formation of surfactant and polymer layers at solid-liquid interfaces using advanced spectroscopic techniques will be investigated. The research will utilize near-field scanning optical microscopy, lifetime chemical imaging, 2-photon fluorescence spectroscopy with fluorescence, ESR, electrokinetic, wettability and microcalorimetric techniques. This should lead to optimization of industrial processes and commercial formulations involving surface-active agents.

EEC-9804618 P.I.: Somasundaran Columbia University ABSTRACT Surfactants are used in every major industry of modern society. The aim of this Industry/University Cooperative Research Center for Advanced Studies on Novel Surfactants (IUCS) at the Columbia University is to develop a knowledge base on the relationship between the structures of different surfactants and their performance in various manufacturing systems, products and devices. Modification of classical surfactants with specific functional groups so that their surface, micellar, membrane, and adsorption activities are enhanced or controlled will be one of the approaches in the development of novel surfactants.

ABSTRACT
CTS-9905217
Somasundaran, P.
Columbia University

A large number of aqueous and non-aqueous based systems in the nature and commerce contains one or more polymer and surfactants in the same solution or suspension. In such systems, interactions between polymers and surfactants, as well as changes resultant in properties conferred by any "complex" formed by such interactions, can be of considerable importance in biological systems such as membranes and carriers (lipid transport), and commercial systems of foods, pharmaceutics, cosmetics, detergents and various other chemical systems. Many commercial products containing such mixtures has been widely used in different areas, but formulation of these products has mainly depended on trial and error tests. Clearly a full knowledge of the interaction characteristics of relevant polymers and surfactants will greatly aid the development of efficient products. Toward this purpose we propose to acquire an analytical ultracentrifuge comprising two optical systems for determining concentration distribution. Two important types of experiments can be performed with the analytical ultracentrifuge: in the sedimentation equilibrium experiments, a steady state condition is allowed to develop in which the tendency of a sample to sediment in the centrifugal field is counterbalanced by its tendency to diffuse against the concentration gradient so established. In the sedimentation velocity experiment, the speed with which a molecule moves toward the bottom of the cell is determined. This yields the sedimentation coefficients, and the diffusion coefficient D, which can be related to the molecular weight and the frictional coefficient related to the shape of macromolecules ranging in size from several thousand to tens of millions of dolton. Studies that can be conducted on the dynamics of interactions of polymers and surfactants in solutions using this technique would provide a quantum leap in our knowledge of the behavior of surfactants, polymers and their mixtures. We will be able to use analytical ultracentrifuge also in our study of surfactant, mixtures to understand the relationship between surfactant type, mixing ration and the shape, composition and structure of mixed micelles. Another application will be in our work on coating and coagulation of nanosized particles for preparation of nanocomposites that could lead to significant advance in composite fabrication. Recently, we have expanded our studies of surface adsorption phenomena into the area of polymer (protein)-surfactant mixture systems. The unique capability of the Analytical Ultracentrifuge to provide direst information on the molecular weight distribution of polymer (protein)-surfactant complexes is invaluable in the study of Nan-size polymer-surfactant domains and the solubility of these domains. The acquisition of an Analytical Ultracentrifuge System will thus great enhance the capabilities of Columbia University NSF IUCR Center for Advanced Studies in Novel Surfactants, and will enable us to explore the rapidly expanding frontiers of surfactant and polymer applications.

0117622
Somasundaran

Description: This award supports US-India cooperative research entitled "Modeling Flocculation-Dispersion of Colloidal Suspensions in a Particle Population Balance Framework." Flocculation and dispersion of colloidal suspensions are important unit operations in many industrial activities such as pulp and papermaking, mineral and ceramics processing, and water treatment. The investigators will undertake a detailed study of the nine enumerated steps in the flocculation/dispersion process. They will develop a comprehensive mathematical model that includes a variety of phenomena such as aggregation, interparticle forces, hydrodynamics and polymer adsorption. Although flocculation processes have been extensively modeled, the proposed work will be the first attempt to integrate the various subprocesses. The new model will be validated by comparison with existing experimental data. Predictions from the model will then be tested by performing new experiments.

Scope: The collaborators for this research are P. Somasundaran, Columbia University and P. Pradip and P.C. Kapur, Tata Research Design and Development Centre, Pune, India. The PIs are a team of world class scientists that have an excellent chance of achieving their research objectives. Development of a comprehensive model to predict the kinetics of flocculation will be very useful for water purification, waste treatment, product formulation, mineral beneficiation schemes, and environmental remediation.
This project is jointly funded by the Division of International Programs and the Government of India's Department of Science & Technology.

0117627
Somasundaran

Description: This award supports US-India cooperative research entitled "Microbe-Mineral Interaction Mechanisms Relevant to Precious Metal Extraction with Environmental Control." The PIs will investigate bioprocessing for the enhanced recovery of precious metals such as gold, silver and platinum and will focus on the mechanisms by which certain microbes adhere to different mineral surfaces and alter interfacial properties. These mechanisms are as yet not very clear. During leaching, metal ions accumulate; some of which may confer toxicity to bacteria. There is need to understand the toxic metal tolerance of selected bacteria and develop more efficient metal tolerant strains.

Scope: The collaborators for this research, P. Somasundaran, Columbia University and K. Natarajan, Indian Institute of Science, Bangalore, have worked successfully in the past and have published in major international journals. Due to growing environmental awareness during the past decade, the use of biotechnology has become attractive as an environmentally benign, cost and energy efficient means for mineral beneficiation and environmental control. This project is jointly supported by the Division of International Programs and the Government of India's Department of Science & Technology.

0091547
Somasundaran

This two-year award, which supports U.S.-Italy cooperative research on interactions of nanoparticles of dendrimers/liposomes with polymers and surfactants, involves Ponisseril Somasundaran of Columbia University and M.F. Ottaviani of the Institute of Chemical Sciences in Urbino, Italy. The objective of their research is to enable the use of electron spin resonance to monitor conformation of polymers and surfactants at interfaces.

The U. S. principal investigator brings to this collaboration his group's expertise in identifying the best conformation of polymers and proteins for determining the interactions between nanoparticles and dendrimers with surface active species. The US co-PI provides experience with applied supramolecular structure-function and structure-reactivity relationships toward understanding the behavior of adsorption at interfaces. This work is complemented by the Italian investigator's expertise in the use of electron spin resonance probes for examination of adsorption at interfaces. The results of this research are expected to contribute to knowledge of the behavior of vital industrial systems.

Abstract
CTS-0132364
Somasundaran, P
Columbia U

SURFACE TREATMENT OF FIBERS USING NEW SILICONE BASED SURFACTANTS

Fibers and fabrics used for the manufacture of various protective barriers are normally
subjected to finishing operations for desired modification of their surface properties. Although many of these processes have been practiced, for example for over 30 years in the fabric industries, there are significant process variations. The process development and formulation optimization are established mostly through empirical approaches without the understanding of the fundamentals of these processes. This creates a lack of general guidelines for modifying different new fibers/fabrics/membranes as they are introduced into the industries. The objective of this exploratory project is to develop a basic understanding of the finishing processes used and to elucidate the role of the parameters responsible for its surface characteristics and performance properties. This will involve measurement of the reagent adsorption/adhesion, molecular conformation and orientation of the adsorbents, interactions among reagents such as polymers and surfactants, nano-structures of the surface aggregates formed by these reagents and
correlation of the results to the fabric surface properties such as surface charge, hydrophobicity and fluid penetration. As the proposed research has the objective of controlling the surface properties using a new class of surface modifiers based on silicones, the outcome should make a significant contribution to the advancement of fabric/membrane products. Testing of these compounds is admittedly a high risk attempt but if perfected should lead to safer and eco-friendly products with enhanced performance. Towards this purpose, the next step will involve study of interactions of designed nanoparticles with fabrics and their crosslinking for superior finish, fire resistance, durability and chemical and biological agent resistance.

This is a tie project between the Industry/University Cooperative Research Center for Biocatalysis and Bioprocessing of Macromolecules at the Polytechnic University of New York, and the I/UCRC for Advanced Studies on Novel Surfactants at Columbia University, New York. The research program includes (1) synthesis of new functional polymers from renewable resources by selective biocatalytic transformations, and (2) investigation of fundamental relationships between the polymer structures, adsorption and conformational characteristics at surfaces and interfaces. Surface and interfacial properties of the polymers and copolymers synthesized at the Polytechnic University will be studied at the I/UCRC at Columbia University. A companion award (EEC-0124037) will support the research at the Columbia University.

This is a tie project between the Industry/University Cooperative Research Center for Biocatalysis and Bioprocessing of Macromolecules at the Polytechnic University of New York, and the I/UCRC for Advanced Studies on Novel Surfactants at Columbia University, New York. The research program includes (1) synthesis of new functional polymers from renewable resources by selective biocatalytic transformations, and (2) investigation of fundamental relationships between the polymer structures, adsorption and conformational characteristics at surfaces and interfaces. Surface and interfacial properties of the polymers and copolymers synthesized at the Polytechnic University will be studied at the I/UCRC at Columbia University. A companion award (EEC-0124037) will support the research at the Columbia University.

0103246
Somasundaran
This proposal was submitted in response to the solicitation "Nanoscale Science and Engineering" (NSF 00-119).

Research in nanotechnology has to date concentrated mainly on the equilibrium properties and behavior of nano-systems, with the dynamics of the system rarely studied. This study is based on the conviction that elucidation of the basic mechanisms of dynamics will help in developing materials of the future which will have an inherent smartness built into them. For example,
adsorbed polyacrylic acid structures will undergo coiled to stretched/dangling conformational changes upon changing the pH. This can produce a marked response in the dispersed state of suspensions. This project will focus on the dynamic behavior of novel nano-structures and their
active groups as a function of electrical, chemical, magnetic, thermal and optical fields.

Some of the topics to be evaluated are 1) how the conformation of polymers changes and how rapidly they do so under changing pH, thermal, electrical, optical, magnetic and acoustic fields, 2) how the response of the active groups can be manipulated to develop novel structures, 3) how the properties of the nano-composites change as a function of their structure if a sinusoidal field is applied during the preparatory stage, and 4) what happens if variations and perturbations in
the field take place after the preparation.

The general methodology involved is to add a probe to a target molecule, which would respond to external perturbation vectors. This response would induce conformational changes in the adsorbed target molecule which will be followed in real time. For changes in pH we have carboxylic acid groups as probes, for magnetic field we will use aqueous ferro-fluids (hematite nanoparticles stabilized by surface active agents) and for optical perturbation we will use "azo" groups. These will be adsorbed on surfaces of silica (for AFM), gold (for SPR), and alumina (for ESR and fluorescence) functionalised for the binding of the modified macromolecules.

The first stage of the research project involves synthesis of macromolecules incorporated with these probes. In the second stage, the dynamics will be studied using AFM, ESR, SPR and fluorescence spectroscopic techniques, while the molecules are being perturbed. It is the final goal to use the information gathered in the second stage to build novel nanomaterials with controllable properties.

ABSTRACT
CTS-0089530
Columbia University

The goal of the proposed research is to investigate the formation of surfactant aggregates in mixed systems and particularly the dynamics involved. As the experimental system is complex the strategy involves use of multi-pronged approach, combining several techniques such as ultra-filtration, analytical, centrifuge, micro-calorimetry and AFM, with advanced spectroscopic techniques including Surface Plasmon Resonance Spectroscopy, fluorescence and ESR. The goal is to determine the relationship between structures of surfactants and their properties as determined by the shape, composition and structure of mixed micelles and hemimicelles. Based on these results a recent theoretical model will be refined to enable prediction of the formation of surfactant aggregates in their mixtures and changes in them.

Surfactants to be studied in this proposal will include environmentally benign sugar-based and pyrrolidone-type surfactants. The investigators have seen that these surfactants do show unusual selectivity in their adsorption on solids, but the reasons for the selectivity are not known. Similarly, another important example is the synergy observed between the thiol surfactants in flotation, which is not well understood. Study of their synergy will be a collaborative effort between us and the University of Cape Town, South Africa group which has been studying the issue from a thermodynamic point of view. The proposed research will enable the investigators to advance the frontiers of surfactant colloidal chemistry by acquiring new information on the formation of surfactant aggregates in their mixtures. Such information will make it possible to develop opportunities to fully utilize the unique nano-environment provided by mixed surfactant aggregates for particle processing, ultra-purification, reactions in nano-domains as well as controlled release from such domains.

Surfactants and polymers are used today in every major industry including household and personal care, imaging, printing, advanced mineral and ceramics, petroleum and fuel, micro-electronics, pharmaceuticals, food processing, paints and coating, and environmental control. The Industry/University Cooperative Research Center for Advanced Studies in Novel Surfactants (IUCS) at Columbia University was established in 1998 to elucidate the behavior of different surface active molecules and their mixtures and to develop new processing schemes that depend critically on the structure and function of conventional and novel surfactants. The major aim of the center is to develop a knowledge base on the relationship between the structure of different surfactants and their performance in various industrial processes, characterize their solution and interfacial behavior and identify suitable industrial applications. It is also an aim to develop novel specialty surfactants that are "environmentally benign" for specific applications in the chemical industry.

Somasundaran, Ponisseril
Columbia University

"SGER: Aptamer-based Nanogels: Chemosensory Transducers and Sensors for Homeland Security"

Recent events have necessitated development of advanced sensors for rapid detection of toxins and microbes. It is the principal investigator's aim to develop smart aptamer (oligonucleotides of modest size) based polymeric nanogel platforms that would sense external perturbations, and respond appropriately. The investigator will incorporate DNAzymes (self cleaving aptamers) into nanogels so that they will release a pre-loaded antidote or produce a detectable signal upon binding of a toxin. The interfacial and colloidal properties of the synthesized nanogels will be studied using fluorescence spectroscopy, light scattering studies and ultra centrifugation while their delivery processes at the interface between nanogel and ligands will be studied using surface plasmon resonance spectroscopy in real time.

Broader Impact: This nano-scale research project has been envisioned and conceived as a strongly interactive and collaborative program between the participating PI's in different disciplines---chemical engineering, biology and chemistry. It has potential applications in as diverse areas as microelectric circuits, sensors, nano-computers, cosmetics and bio-mimetic devices. Undergraduate students from a diverse body will have an opportunity to participate in this on-the-horizon technology through Columbia's current educational programs and focused outreach activities.

Somasundaran, Ponisseril
Columbia University

" Fluorescence Spectrophotometer to Investigate Nanostructures at Interfaces."

This project is for the procurement of a Fluorescence Spectrometer, for the Langmuir Center for Colloid and Interfaces of Columbia University, New York, for the research of an interdisciplinary research team, investigating novel nanostructures and their dynamic behavior at various interfaces. The principal investigators who will use this instrument include Prof. Chasin (Biology Dept.), Prof. Gryte (Dept. of Chem. Eng.), Prof. Somasundaran (Earth and Env. Eng.) and Prof. Turro (Chemistry Dept.).

Adsorption of nanoscale surfactants and polymers is used for the modification of the surface properties of solids and finds application in many industrial processes such as flocculation/dispersion, deposition, coatings, enhanced oil recovery and flotation. Efficient use of adsorption in these cases depends not only on the amount adsorbed but also on the nano structure of the adsorbed layer in terms of the conformation and orientation of the adsorbed species. Currently there is very little information on conformational aspects of the adsorbed species, mainly due to lack of reliable in-situ techniques. Their earlier work focused on understanding the physico-chemical mechanisms of adsorption of surfactants, polymers and proteins by studying adsorption density, zeta potential, wettability and calorimetric effects. Such investigations have helped in generating a mechanistic picture of the structure of the adsorbed layers. More recently, Turro, Somasundaran and Gryte have collaborated in using fluorescence spectroscopy along with electron spin resonance spectroscopy (ESR) to probe adsorbed surfactant and polymer layers on particles, liposomes, implants etc. These studies have demonstrated the potential of fluorescence spectroscopy to investigate the nano-structure of adsorbed layers. With this new fluorescence instrumentation available, there is an unprecedented opportunity to investigate the conformational aspects of species at interfaces on a sub molecular level (nanoscale).

Broader Technical Impact: This instrument will be used to develop a full understanding of the interactions of surfactants and polymers / proteins, particularly the nano-structures of adsorbed layers and colloidal aggregates and the effects of different parameters on the structure. Knowledge about the conformation of the dissolved and adsorbed species and their dynamic behavior will prove useful for developing smart materials responsive to the presence of contaminants, bioagents and perturbations in parameters such as pH, temperature and ionic strength. The instrument will be used ton a multitude of projects, most of which are aimed at improving our understanding of molecularly assembled systems and are important to basic science and advance in technologies. Because the instrument is being shared among several researchers and will be used on several independent projects in different disciplines, it is likely that the spectrophotometer will be used by a large number of students and postdoctoral fellows. The instruments will also offer training opportunities for undergraduates.

This action provides funds for the University of Florida and Columbia University to hold a planning meeting to establish the Industry/University Cooperative Research Center for Surfactants and Particulate Systems. The focus of this center is to conduct advanced research in particulate systems and surfactants of significance to industry and in close collaboration with industry. The aim of the center is to develop a knowledge base on the interactions between particulate systems and their relationship with the structure of different surfactants for enhanced performance in the pharmaceutical, chemical, micro-electronic, and other nano-bio applications.

This collaborative project joins researchers from the Industry/University Cooperative Research Center (I/UCRC) for Advanced Studies in Novel Surfactants at Columbia University and the I/UCRC for Biocatalysis and Bioprocessing of Macromolecules at the Polytechnic University of New York. The research will focus on understanding how biosurfactant structures can be fin tuned to improve their interface properties, which in turn, will impact their performance. This research will be conducted in two phases; develop a family of biosurfactants and study interface properties. This research has the potential to significantly impact the use of biosurfactants in the medical area.

This collaborative effort will have a broad impact on participating students, industry and faculty members and will increase the research base for biosurfactants. The research will help towards the development of a variety of biosurfactants that will suit the needs of industrial applications.

This proposal formally establishes a multi-university Center for Particulate and Surfactant Systems as part of NSF's Industry/University Cooperative Research Center (I/UCRC) program. The University of Florida (the lead institution) and Columbia University will maintain research sites to collaborate on research. The proposed center's goal is to develop a knowledge base on the interactions between particulate systems and their relationship with the structure of different surfactants for enhanced performance in the pharmaceutical, chemical, microelectronic, and other nano-bio applications. The research thrust areas identified in the proposal include synthesis, characterization, processing and applications.

The proposed activity involves a number of researchers from different disciplines from both universities. Much of the research will be carried out in collaboration with a number of industrial researchers. The proposed I/UCRC research program will contribute to a timely development and commercialization of targeted research of major societal significance. Work force development through education and advanced training of students will be a resource to industry and academe in this critical field of science and engineering and surfactant systems. In addition, recruitment of women and under-represented groups will be emphasized.

PROGRAM DIRECTOR'S RECOMMENDATION

IIP-0942962
Columbia University
Somassundaran

This proposal is a collaborative (TIE) project between Columbia University (a research site of the I/UCRC for Particulates and Surfactants) and the Indian Institute of Technology (IIT), Madras. The objectives of this joint research are very much in line with this Center's goals in the "green initiative" area.

This TIE project outlines research for the development of a pathway for producing commercial surfactants under anaerobic conditions, which is unique as most of the biosurfactant producers reported in literature are aerobic organisms. The proposed work will be extremely valuable for understanding of and optimization of structure/activity relationships. The thorough evaluation of the biosurfactants will make their use as cleansers and surface modification agents a viable application; thus, opening an environmentally-friendly, renewable source for surfactants currently generated from petroleum sources. The proposed work can be accomplished effectively given the expected good synergies between surface chemistry (Columbia University) and experiences in the area of microbial growth in confined, porous media in IIT (within the general area of civil and environmental engineering).

The information from this TIE project will have a broad impact on participating students, and should be useful to may industries: soil cleaning, oil spill cleaning, cosmetics, coating and mineral processing. This project will start a USA-India network; and, student and research exchange will be a plus. The Columbia group will continue to train women graduate and undergraduate students in the surface and colloidal science.

CBET-0852358
Somasundaran

This group travel project is for a combined meeting being held under the sponsorship of the National Colloid and Surface Chemistry Division of the American Chemical Society (ACS) and the International Association of Colloid and Interface Scientists. The sponsors along with five presenters will participate in the 13th IACIS and 83rd ACS Colloid and Surface Science Conference in New York. The two meetings will be held jointly on the campus of Columbia University during the week of June 14-19, 2009.

Intellectual Merit: Many of the topics impact on nanotechnology in the 1414 program; the topics are: (1) Interfaces and Interphases: Thermodynamics, Structures and Adsorption including: (2) Particulate Systems including: Rheology and Soft Matter Physics (3) Surface Active Agents.

Broader Impact: The annual conference has been held over the past several years at university campus locations rotated throughout the United States. The joint hosting of the meetings presents a unique opportunity to draw from a large group of researchers globally, thereby insuring a forum in which a very diverse set of ideas will be presented. Attendance at the conference insures cross fertilization of research ideas potentially leading to greater advances in the fields.

The PI is requesting foreign travel money to provide international travel for four conference presenters to travel from Norway, Australia, Japan and the United Kingdom to New York City.

0933621
Somasundaran

This project is for the acquisition of an analytical grade confocal Raman microscope for the UFL/CU I/UCRC NSF Center for Particulate and Surfactant Systems (CPSS) at Columbia University, for a shared use with other departments. The instrument is essential in advancing current and planned research at CPSS in such areas as 1) health and environmental safety and chemical reactivity of nanoparticles (NPs); 2) greener chemicals for industries; 3) new silicone surfactants and polymers with enhanced performance. Among current projects in the Department of Earth and Environment Engineering and other departments which would also definitely benefit from the use of Raman are: 1) carbon dioxide sequestration, alternative energy, gas separation membranes; 2) biocolloid engineering for medical applications in molecular imaging and targeted therapy; 3) determination of geological processes through identification of dissolved volatiles in high silica magmas, identification of mineral phases in multi-micron sized inclusions within host crystals; 4) new nanoelectronical systems; unique electronic, rotational, vibrational and spin interactions between an incarcerated guest molecules with the inner concave walls of a C60 host.

Intellectual Merit: 1) Unique, fast, accurate, and non-intrusive techniques of Raman spectroscopy will be developed for in situ locating of NPs and characterizing of their electronic, surface, and lattice properties, wettability, agglomeration, and deposition as well as reactivity (adsorption, acid-base, redox properties, and the capacity of NPs to generate or scavenge reactive oxygen species, interaction with cell membranes) at natural and engineered interfaces as well as in cells, bacteria, emulsions, and suspensions. 2) Based on the scientific data obtained through Raman and other complementary spectroscopic and microscopic methods, a new paradigm of nanotoxicity of NPs will be developed. 3) In combination with other experimental methods and theoretical modeling, Raman microscopy will be used to understand the synergistic effects of green surfactants with conventional surfactants, polymers and their hybrids at molecular and upramolecular levels. Fundamental mechanisms and predictive models for the aggregation behavior and structure-performance relationship will be proposed and tested. 4) For the first time, a systematic fundamental vibrational spectroscopic study will be performed on the surface and interfacial activity of silicone surfactants/polymers on cotton fabric, as a function of silicone molecular architecture. The information generated will be used to expand the existing knowledge base to develop new hybrid silicone structures and to identify other materials with unique interfacial properties.

Broader Impact: The use of Raman microscopy in our research efforts will allow 1) the generation of critical knowledge required to address challenges in the emerging fields of green technologies, nanotechnology and nanoscience, colloid science, geoscience, medicine, and materials research; 2) the development of new technological solutions based on a better understanding of novel and complex materials and their interactions with biosystems at the molecular level, in particular, fostering innovation in a broad range of industries that employ surfactants, polymers, and nanoparticles; 3) the enhancement of interdisciplinary and inter departmental collaboration; 4) the training of undergraduate and graduate students on an instrument with utility across a wide range of disciplines, promoting their education and their team interaction; 5) the expansion of the scope of the spectrochemistry community into the emerging areas of applied sciences and engineering, which will certainly boost new high quality interdisciplinary research. The research will help to increase the number of minority students in various laboratories, as we are aiming to train more minority students through the Engineering school's special Undergraduate Research Involvement program. Minority students will benefit through first hand experience in methods of scientific research, working with advanced analytical techniques, and learning about their applications in industrially relevant areas. The PI will integrate a part of the employed experimental studies to develop a laboratory module for use in his courses Introduction to Surface and Colloid Chemistry and Applied Surface and Colloid Chemistry.

The BP oil spill began on April 20th, 2010 and leaked oil into the Gulf of Mexico at a rate of 35,000 to 60,000 barrels per day for a period of about three months. Various technologies have been deployed to attempt to collect or disperse the oil and to minimize damage to wildlife and property. This includes the use of about 1 million pounds of chemical dispersants to disperse the oil. The large-scale introduction of dispersants into the environment has led to an intense focus on the safety and environmental impact of these chemicals. The objective of this project is to develop "bio-dispersants" that are effective and minimally toxic to key organisms native to the Gulf of Mexico. The bio-dispersants will be produced by the natural process of fermentation. Specifically, microorganisms will be used to convert underutilized agricultural residue (for example, soybean hulls) into bio-dispersants. Gene engineering methods will be used in the laboratory to generate many different pure cultures of the microorganisms, each of which produces a different bio-dispersant. Each bio-dispersant will be purified, and the ability of each bio-dispersant to disperse oil will be measured. Bio-dispersants that are effective will be tested to determine whether they are toxic to key organisms, the benthic infauna, which are important members of the Gulf food chain and ecosystem. The objective of this research is to use iterative rounds of design, production and testing to discover bio-dispersants that are safe and effective. All significant findings from this work will be published promptly. All results and data collected as part of this research will be made available to other researchers.

Broader Impacts.
The integration of computer design tools with robotic manipulation enables the use of cellular and molecular biology to produce new chemicals and materials. The field created by the convergence of computer science, robotics and biology is called "synthetic biology". There was a revolution in chemistry that occurred between 1930 and 1960, typically referred to as the "synthetic chemistry" revolution. It was during that period that scientists and engineers learned to use petrochemical feedstocks to produce the vast array of organic chemicals, polymers and plastics available to us today. We are in the early phase of a new revolution in chemistry. In particular, "synthetic biology" is enabling engineers to generate the chemicals and materials needed by our society from renewable raw materials, similar to the way "synthetic chemistry" enabled the production of organic chemicals from petroleum. Synthetic biology is enabling a "sustainable chemistry" revolution, which represents a significant opportunity for America because it depends on combining three areas of U.S. strength and excellence: agriculture, biotechnology and chemical manufacturing. According to the BIO Organization, sustainable chemistry could lead to the generation of $190 billion in domestic revenue from chemical sales, and to the creation or retention of 237,000 U.S. jobs. This research project represents a collaboration between a leading company in this important field, Modular Genetics, Inc. and scientists at three universities: Columbia University, Iowa State University and Louisiana State University. This project should simultaneously lead to the launch of new commercial products, and to the training of scientists and engineers prepared drive this industry forward.

Have you ever wondered at the variety of self assembled deposit structures that can be obtained by evaporating liquids containing nanoparticles on top of a solid substrate. Deposit shapes vary from rings around a coffee drop, to hexagonal cells and fractal patterns. An interdisciplinary team of Columbia University scientists will study the related fascinating multiscale physics, using a combination of experimental, theoretical and numerical techniques. The team has the following skills: multiphase flow (Attinger, PI), colloids (Somasundaran), pattern recognition (Chang) and open-source computational fluid dynamics (Spiegelman). The complex self-assembly of nanoparticles will be studied by using first physical principles to explain the resulting selfassembled patterns (what we call a top-down approach), and by identifying features in the patterns that are signs of specific basic laws or transport rules (bottom-up approach).

Intellectual Merit:

Experiments will involve the spotting of microdrops of complex fluids on various substrates, fluorescence microscopy and laser profilometry to scan the three dimensional deposits. The first intellectual merit will be to describe with a phase diagram the self-assembly of nanoparticles during liquid evaporation on a solid substrate. The use of a phase diagram in that context is novel and allows a simple but powerful comparison of the magnitude of competing transport phenomena, such as evaporation at the wetting line, Marangoni recirculation, electrostatic and van der Waals forces, buoyancy, and dielectrophoresis. The phase diagram will provide an insight and an overview of the complex interplay between multiphase processes, influenced by the geometry of the liquid drop or film: fluid mechanics, heat transfer, mass transfer, colloidal interactions. Second, an available proprietary 2D-axisymmetric numerical code with a moving mesh able to very accurately track the free surface will be extended to 3D (see Chandra collaboration letter). This will allow the simulation of a wider ranges of boundary conditions, permitting the consideration of thin films and complex geometries. Explaining the self-assembly of nanoparticles from evaporating drops and liquid films from first principles is a challenging approach, given the multiple transport phenomena and time/length scales. Therefore, we will also develop a bottom-up approach based on pattern recognition of selfassembled features. We will test the hypothesis that the patterns tell us the about the physics that created them.

Broader Impact:

The proposed research will deliver innovative solutions to pattern nanoparticles on solid substrates, with applications in organic electronics and patterning of biomolecules for biosensors. Methods to increase printing resolution by two orders of magnitude (see Sonoplot letter), and to pattern uniform layers of particles will be investigated. The pattern recognition algorithms developed in this proposal will be tested to identify biomolecules (see Zenhausern letter) and enhance the accuracy of bloodstain pattern analysis, in collaboration with forensics expert MacDonell (see collaboration letter). Also, the 3D code developed in this proposal will be distributed freely as an open-source code, allowing every interested scientist to study problems involving drop and film transport phenomena such as drop impact, drop evaporation, film drying. Funding will support one graduate student.

1052697
Somasundaran

The investigators will evaluate greener, nano-scale, bio-surfactants based solutions to the problems of spreading of oil and cleaning of the spill from the shore and Marsh lands. Oil soaked in beach sands and marsh lands has already affected the ecosystem dramatically. Besides, the issues persist for several years and environmentally benign solutions are still lacking. Thus an urgent need is to develop greener solutions to preserve the ecosystem. Our approach will be utilization of bio-surfactants to study the solubilization of crude droplets without the influence of shear. It is also important to remove the solubilized oil from beach sands and marsh lands with minimum disturbance to the areas. First, to model the removal of oil from beach sand in a laboratory set up, the work will include quantifying coalescence, reaction and transport in several multiphase systems in transparent porous media pack. Furthermore we will treat beach sand with bio-surfactants followed by separation of oil using flotation or hydrocyclones. Second, solubilized oil in marsh lands can be treated to form a separate phase over water and be removed. To explore this idea, the investigators will determine rheological properties of oil solubilized using biopolymers and also by manipulating conditions such as pH, and salinity to obtain desired separation. For long term solution, the PIs will explore microbial-oil interactions to degrade oil. Though all the above mentioned procedures are applicable, the oil has formed a thick layer and cruds in and around the water in Marsh lands. The PIs will evaluate technologies to mechanically remove such oil by various techniques as flotation and using hydrophobic fibers.

Intellectual Merit: The project will provide fundamental understanding of the structure-property relationships of various greener bio-surfactants in oil solubilization. Fundamental aspects will relate to spatial arrangement of functional groups, effect of carbon chain length and biodegradability of the greener surfactants. Further, the proposed study of transport through packed bed should yield fundamental insight into the mechanisms of attachment and resultant changes in wettability on the flow of the oil through complex porous systems.

Broader Impact: With growing global concern over the toxicity and poor biodegradability of surfactants/polymers used in of industries, recent focus has been on application of greener bio-surfactants/biopolymers. Various sectors interested in such greener reagents range from mineral processing, alternative energy, personal care, food industries, and petroleum industries. The research findings on structure property evaluation should provide valuable insight in evaluating reagents for their greenness based on the structure of the molecules. The multidisciplinary subject of the proposed research will attract talented students from diverse groups.

Program Director's Recommendation
Center for Particulate and Surfactant Systems (CPaSS)
Proposal # 1230367 & 1230680
Moudgil and Somasundaran

This proposal seeks funding for the Center for Partculate and Surfactant Systems (CPaSS) located at the University of Florida (lead site) and Columbia University. Funding Requests for Fundamental Research are authorized by an NSF approved solicitation, NSF 11-570. The solicitation invites I/UCRCs to submit proposals for support of industry-defined fundamental research.

This proposal will investigate foaming properties of green surfactants and the effects of presence of fine particles on foaming and frothing behavior. The primary goals of the proposal are 1)to understand physico-chemical aspects of the foaming/defoaming properties of green surfactant formulations and surface modified fine particles; 2)study the structure of surfactant films at the liquid-gas and solid-liquid interfaces; and 3)to develop efficient foaming/defoaming formulations. Experiments will involve the macroscopic measurements of foam/froth stability and a vibrational FTIR and Raman) spectroscopic study of the molecular organization of green surfactants in the liquid films of foams. A new FTIR spectroscopic method will be employed to acquire spectra of unstable bubbles. Dissipative Particle Dynamics (DPD) computational simulation will be used to simulate the green surfactant systems. The DPD modeling will be adapted to facilitate interpretation of experimental data.

Results of this study will advance the fundamental understanding of the parameters that govern the antagonistic and synergistic effects of green surfactant formulations and their mixtures with modified fine particles on the foamability, frothing, and defoaming of the solutions and suspensions. The industries interested in the proposed fundamental studies include green surfactant producers, mineral processing, petroleum, paints and coatings industries, biochemical separation, cosmetics, personal care, and household products industries, as well as those interested in the environmental remediation. Specifically, a comprehensive understanding of the foam stability of green surfactants will lead to the development of new formulas for their applications in personal care and cosmetics products, while the knowledge about the fine particles interactions with green surfactants will lead to the development of cost effective foaming, frothing, and de-foaming systems.

PI: Somasundaran, Ponisseril
Proposal Number: 1242524
Institution: Columbia University
Title: EAGER: Elucidating Protein - Colloid Interactions for Enhanced Bio-Energy Applications

An emerging trend in alternative energy technologies is the use of enzymes or other functional proteins to generate energy; this can already be seen in bio-fuel efforts, where enzymes are used to break down crystalline cellulose into simpler sugars. More radical approaches to ?bio-energy? include bio-fuel cells, where enzymes are the catalysts that oxidize sugar to generate a current; or bio-solar which takes advantage of photosynthetic proteins to capture and harness photonic energy. The ecological advantages are apparent: enzyme catalyzed processes are low temperature and require no harsh solvents. However, the challenge lies in finding ways of maximizing their stability and function outside of a biological environment.

The goal of this EAGER project is to explore the unknown interactions that arise from protein ? colloid interactions; specifically those that enable active portions to seemingly ?perceive? their environment through the protein structure in which they are embedded. Whatever mechanisms responsible for these macromolecular sensory phenomena may be responsible for the synergistic interactions which occur between non-ionic surfactants and enzymes, resulting in increased enzyme activity.

PI hypothesizes that surfactant aggregates (micelles) interact with the external structure of enzymes to affect changes in fluctuations, causing sub-angstrom scale dynamic motions which ultimately affect the active site position and range of motion. The PI will study this novel concept through a exploratory research plan - starting with a foundation in comparing enzyme kinetics, to understanding colloid and protein structure behavior, and then molecular dynamic modeling. From these observations, the PI intend to develop a thorough model of the physical interactions that occur between the enzyme structure and surfactants as well as surfactant-aggregates, with the ultimate goal of determining if there is a connection between non-ionic surfactant micelles, enzyme structure flexibility and enzyme activity.

This previously unexplored concept attempts to build a bridge between the bulk interactions of enzyme kinetics in crowded colloid systems with the atomic scale motions and forces that dictate elements of protein flexibility and selectivity. Because the PI are seeking to find agreement between two extremes of observable phenomena, a multidisciplinary approach is required; including but not limited to studying the bulk macromolecular phenomena that are indicative of the state of protein structure dynamics, such as reaction kinetics, static structure spectroscopy and colloid physics. The PI will then correlate these findings with investigations with novel techniques in 2d spectroscopy and molecular dynamics modeling to investigate pico-scale spatial and temporal phenomena, stopping short of regions where quantum effects begin to complicate observations.

This project has implications for biofuel and for several fields outside of alternative energy, such as: home-personal care, waste management and medicine, possibly reducing the chemicals consumed for various applications by taking advantage of synergies between them and protein structural conformation dynamics. The PI will use this project to train and engage undergraduate students, particularly those from targeted groups, who have become attracted to such Green projects. In as much as this has yet to be substantiated, this broad interdisciplinary scope of investigation, coupled with emerging instrumental techniques, and prospective implications to the tangent fields mentioned above, mark this project as a ?high risk and high reward? situation, and an appropriate EAGER submission.

PI: Somasundaran, Ponisseril
Proposal Number: 1336845
Institution: Columbia University
Title: SusChEM: Rational design of aqueous interfaces of Earth abundant and nontoxic transition metal sulfides for photocatalytic conversion of CO2 to fuels

This project focuses on understanding aqueous interfaces of Earth abundant and nontoxic transition metal sulfides to engineer a cost-effective photo-electrocatalytic CO2 reduction system. The biggest roadblock to making scalable the sun-light powered synthesis of carbonaceous fuels from CO2 and water is the lack of a catalysts which is simultaneously efficient, cheap, and environmentally benign. The development of such a catalyst is hindered by the infancy of the mechanistic understanding of the proton-coupled multiple electron transfers involved into the CO2 reduction beyond CO and formate. The proposed interdisciplinary research will bridge this knowledge gap by systematically studying for the first time copper and iron sulfide minerals as novel and cheap photocatalytic materials. A novel molecular cocatalytic approach is suggested to overcome the thermodynamic and kinetic limitations of CO2 reduction towards energy-dense fuels. The objective is to determine the mechanisms of the reaction dependence on molecular cocatalysts at the interfaces and in bulk electrolyte, with the ultimate goal to develop more sustainable and efficient photosynthetic systems. Towards this ambitious goal, a team from Columbia University will study for the first time the multiscale physics and chemistry driving artificial photosynthesis of carbonaceous fuels by iron and copper sulfides, using advanced operando FTIR and Raman spectro-electrochemical, (photo)electrochemical, and theoretical (e.g., Density Fuction Theory) methods.

The new more efficient photosynthetic systems based on copper and iron sulfides developed during the research will be a practical step towards scaling up renewable energy. It will lead to novel scalable strategies for the rational design of the interfaces of metal sulfides with water. Apart from artificial photosynthesis, this outcome can find application in immobilizing radionuclides in environmental remediation, as well as in mineral processing (selective separation) of sulfide minerals, in the design of greener chemicals. In addition, this knowledge will broaden our understanding of biogeochemical process including processes in acid-mine drainage, cycling of iron and cupper in deep oceans, and eventually the origin of life. The general results of the research and the new methodology will be included in the PI's undergraduate/graduate level courses.

In Phase II operation, the I/UCRC for Advanced Particulate Systems and Surfactants (CPaSS) intends to address challenges which fall under two broad categories: 1) characterization of particles and surfactants at nano and molecular scale, predictability in tuning their performance, and environmental and physiological compatibility, and 2) elucidation of understanding of structure-property-performance relationships in particulate/polymer/enzyme systems. To address challenges in fabrication of particles and surfactant systems with tunable properties, development of predictive models to understand their behavior in industrially relevant environments is needed. This requires understanding the mechanisms by which particulate and surfactant systems of different properties behave under industrially relevant dynamic systems - a major theme of the center's Phase II research program.

Particulate and Surfactant Systems are vital to virtually every major industry including pharmaceuticals, detergents, cosmetics, liquid crystals, micro-electronics, advanced ceramics, petroleum and fuels, minerals, agriculture, biotechnology, photography, and paints and coatings. Center research can contribute to efficient process development leading to more effective and less costly consumer products; tools and protocols to screen greenness of reagents and particles together - the platform for many industrial, household and healthcare products. CPaSS is committed to continue and increase the enrollment of women, underrepresented minorities and persons with disabilities during Phase II through stronger interactions with college and university programs that support recruitment of such students into the STEM fields.

The broader impact of this RAPID project is to advance the understanding of a new disinfectant composition. A common approach to contain the spread of infectious diseases involves spraying decontaminating disinfectants onto the floors in hospitals, apartments, parks, airports, footpaths, and other surfaces. The disinfectants commonly used are bleach, hydrogen peroxide, phenols and iodophors. Sprays of such solutions on surfaces do not stick to surfaces of protective clothing and hence have to be applied multiple times a day for decontamination results. Furthermore, such operations can result in seepage of the solutions into the ground. Considering the pandemic nature of infectious diseases such as COVID-19, decontamination practices can often span for months, causing prolonged exposure to disinfectant fumes that may be harmful to the lungs and irritating for the respiratory tract. The proposed project aims to overcome these issues by developing and applying disinfectant formulations as a foam allowing sufficient exposure. A foam with super spreaders can penetrate cracks and crevices, sticking to surfaces long enough to decontaminate. The formulation will be designed for decontamination of floors and windows in houses, vehicles, hospitals, and large areas such as airports. In order to further minimize the use of disinfectants such as bleach, an antimicrobial reagent serving as the foaming agent will be used. This will benefit communities experiencing contagious diseases.

The objective of this RAPID project is to prepare a set of innovative foam formulations that differ in disinfectant and surfactant type, and test them for their foamability and deployment using a sprayer. A biosurfactant surfactin that also exhibits anti-microbial properties will be used as a foam stabilizer. This project will: Determine the air/water interfacial tension as a function of surfactant concentration; study parameters, including the rates of foam formation (foamability) and breaking (stability), as well as bubble size; determine and correlate storage and rigidity modulus values for the foams with foam texture for different air/water ratios; study deployment with a variety of delivery equipment, such as household and backpack sprayer and foam lancer; characterize the time-dependent texture of foam formed on a tile surface and relate it to the foamability, the foam-stability parameters, and the storage and elastic modulus values. The tile surfaces after foam completely breaks down will be analyzed using an electron microscope to assess if disinfectant is deposited uniformly or in the form of patches. This assessment will be verified using the Raman spectroscopic mapping of the tile surface; the interfacial tension data at different ratios of surfactant types provide an estimate of their adsorption density at the air/water interface in the presence of hypochlorite ions in the aqueous phase, while the foam stability parameters provide insights into their intermolecular interactions at the interface and the possibility of synergistic effects among different types of surfactants that govern the stability of a foam.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.