The Surfactant Research Institute (SRI) at Brooklyn College
City University of New York
The Surfactant Research Institute (SRI) at Brooklyn College of the City University of New York has the general objective of acquiring and disseminating fundamental and scientific knowledge in the area of surfactant chemistry, especially related to the applications of surfactants. This objective is being attained through the following programs:
- Fundamental research -- generating new data on the surface and interfacial properties of surfactants that support their use in current and new applications.
- Custom research -- conducted on specific surfactant- related problems suggested and supported by industrial organizations.
- Data collection -- through reading of the literature in the field, especially on chemical structure/property relationships in surfactants.
- Education and Training -- instruction of academic and industrial personnel in the theory and practice of surfactant chemistry through courses (Both full and minicourses) at Brooklyn College or on-site at industrial research centers. Research centers at which courses have been given include those of Clorox, Dow, GAF (now ISP), Lever, Reckitt and Colman, and Stepan.
Staff: The Institute is currently centered on the research group of Prof. Milton J. Rosen, but includes research fellows, both from academia and industry, who bring different areas of expertise to the investigation of surfactant and surfactant- related problems. Research fellows of the Institute include Dr M. Dahanayake of Rhodia, who contributes his industrial experience, and Prof. Lesley Davenport, Chemistry Department, a biochemist specializing in fluorescence spectroscopy, and Prof. C. Forest, Biology Department, of Brooklyn College
Research Support: Support of the research of the Institute comes from both government and industry. Fundamental research on the surface and interfacial properties of highly purified surfactants has been supported by grants from the National Science Foundation and industrial sponsors of the Institute. Past and present Sponsors include: Clorox, Colgate-Palmolive, Dow Chemical, Exxon Research and Engineering, GAF (now ISP), Grace Chemical, S. C. Johnson, PetroChina, Procter and Gamble, Reckitt and Colman, Rhodia, Shell Development, and Texaco. Applied research projects on surfactant-related problems of specific interest to an individual industrial organization are supported by funds from that organization.
Some Examples of Research done at the Institute:
- Biodegradable Surfactants based upon Renewable Resources. A new type of biodegradable surfactants, easily synthesized and based on readily-available and renewable resources, has been developed in the Institute. It is described in a pending patent application.
- Fundamental Aspects of Enhanced Oil Recovery. The mobilization of petroleum from the pores of reservoir rock by aqueous systems depends upon the attainment of ultralow interfacial tension (tension in the 10 -3 mN/m range) at the petroleum/water interface. Research in the Institute, supported by PetroChina (China's largest oil company) has shown that this ultralow interfacial tension can be achieved, and at surfactant concentrations of less than 0.1% in the aqueous phase, by use of surfactant mixtures that, when mixed at the proper ratio, have certain physicochemical properties.
- Gemini Surfactants. Gemini surfactants (sometimes called dimeric surfactants) have two hydrophilic head groups and two hydrophobic groups in the molecules, in contrast to conventional surfactants that generally have a single hydrophilic head group and a single hydrophobic group in the molecule. Gemini surfactants can be ten to a thousand times more surface active than conventional surfactants with similar but single, hydrophilic and hydrophobic groups in the molecules.
In the Surfactant Research Institute (SRI), the relationship between gemini chemical structures and their properties, both fundamental and applied (performance) properties has been investigated. Fundamental properties investigated include: equilibrium and dynamic surface and interfacial tensions, critical micelle concentrations, and contact angles on various solid surfaces. Performance properties investigated include: foaming, wetting, reduction of surface and interfacial tension, dispersion of solids in liquid media, solubilizationn of water-insoluble substances into aqueous media, and emulsification.
- Enhancement of the Performance Properties of Surfactants through Synergism. Synergistic interaction between two different types of surfactants can result in a considerable enhancement in the performance properties (foaming, wetting, reduction of surface and interfacial tension, dispersion of solids in the liquid media, solubilization of water-insoluble material in aqueous media, emulsification). The SRI has pioneered in the study of synergism in the mixtures of surfactants and has developed guidelines for the selection of surfactant mixtures that will exhibit synergism in their properties. Investigations have involved mixtures of conventional and gemini surfactants and mixtures of other novel types of surfactants. Other phenomena involving synergism have also been investigated.
- Superspreading of Surfactants and their Mixture. Certain trisiloxane-based surfactants show "superspreading"; that is, dilute aqueous solutions of them spread on a hydrophobic surface to considerably larger areas than do aqueous solution of any other type of surfactants. This makes these surfactants the preferred materials when good spreading is required in their applications (e.g., spreading of herbicides, insecticides on surfaces). However, trisiloxane-based surfactants are expensive and are unstable at pHs other than 7. Research at the SRI has shown that mixtures of certain, considerably less expensive, non-trisiloxane-based surfactants, can equal or exceed the "superspreading" properties of trisiloxane surfactants. These "superspreading" non-trisiloxane-based surfactant mixtures are the subject of a current patent application.
- Removal of Pollutants from Water by Gemini Surfactants. Passage thought surfactant-treated soil is a method of treating contaminated water to remove pollutants from it. This pollutant removal method has the advantage that the contaminated soil can then be easily treated to remove pollutants and surfactants and the contaminant-free soil regenerated for re-use. Research in the SRI has shown that gemini surfactants can be considerably more efficient and effective than comparable conventional surfactants (with similar, but single hydrophilic and hydrophobic group) in removing pollutants from aqueous media by the surfactant-treated soil solids.
- Estimation of Environmental Effects of Surfactants from their Physicochemical Properties. Determining the environmental effects (toxicity, bioconcentration) of surfactants on marine organisms is a necessary, but time-consuming, tedious, and costly process. To attempt to avoid this, the SRI initiated several years ago, with the support of the Procter and Gamble Company, a project whose objective was to determine whether a valid relationship could be found between some physicochemical properties of surfactants and their environmental effects. The results showed that a linear correlation exists between the parameter, ΔG0ad/Amin, where ΔG0ad is a standard free energy of adsorption of the surfactant at the aqueous solution/air interface and Amin is the minimal hydrated cross-sectional area of the surfactant molecule at that interface, and rotifer (a marine organism) toxicity. The values of the parameter, ΔG0ad/Amin, are readily calculated from surface tension data on aqueous solutions of the surfactant. This correlation has been found to hold for individual anionic, cationic and nonionic surfactants. This work, with support from the National Science Foundation and in cooperation with the Procter and Gamble Company, was extended to mixtures of surfactants.
Some Typical Publications of the SRI
Surfactants and Interfacial Phenomena, Rosen M. J., Wiley-Interscience, New York, 3rd edition, 2004; Japanese translation of the 2nd edition, 1994
Industrial Utilization of Surfactants: Principles and Practice, Rosen, M. J. and M. Dahanayake, AOCS Press, 2000
Surfactants in Emerging Technologies, Rosen M. J., Marcel Dekker, New York, 1987
Some Recent Articles:
Mechanism of the Enhanced Spreading of some Mixtures of Anionic and Cationic Hydrocarbon Chain Surfactants on a Highly Hydrophobic Polyethylene Surface, Rosen, M. J. and H. Liu, J. Surfactants Detgts., accepted for publication, 2005
Ultralow Interfacial Tension for Enhanced Oil Recovery at Very Low Surfactant Concentrations, Rosen, M. J., H. Wang, P. Chen and Y. Zhu, Langmuir 21, 3749 (2005)
Synergism in the Spreading of Hydrocarbon-Chain Surfactants on Polyethylene Film: Anionic and Cationic Mixtures by a Two-Step Procedure, Wu, Y. and M. J. Rosen, Langmuir 21, 2342 (2005)
Surfactant-Surfactant Molecular Interactions in Mixed Monolayers at a Highly Hydrophobic Solid/Aqueous Solution Interface and their Relationship to Enhanced Spreading on a Solid Substrate, Zhao, Q., Y. Wu, and M. J. Rosen, Langmuir 19, 7955 (2003)
Structural Effects on Surface and Micellar Properties of Alkanediyl-bis(sodium N-acyl-alaninate) Gemini Surfactants, Tsubone, K., Y. Arakawa, and M. J. Rosen, J. Colloid Interface Sci., 262, 516 (2003).
For further information, contact: Prof. Milton J. Rosen, Director, Surfactant Research Institute, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210. Telephone: (718) 951-5000 Ext. 2821. FAX: (718) 951-4607. e-mail: email@example.com