ACS Fall National Meeting Report

ACS Fall National Meeting takes advantage of diversity

by Fiona Case

Journal of Surfactants and Detergents, News Section, Volume 7(1), January 2004

The American Chemical Society (ACS) Fall National Meeting was held September 7–11, 2003, at the Jacob K. Javits Convention Center in New York, New York. More than 14,000 attendees participated in symposia organized by technical divisions and committees representing all areas of the chemical endeavor.

   Some of the most stimulating sessions were those that took advantage of this diversity and brought together industrial and academic chemists from different fields. A good example was the symposium on the colloid and surface chemistry of personal-care products and pharmaceutical delivery systems.

   “ Scientists who develop personal-care products and pharmaceuticals delivery systems are often interested in the same fundamental principles, but they apply them to different problems,” said Meyer Rosen of Interactive Consulting, East Norwich NY, who organized this event with Nagu Nagarajan of The Pennsylvania State University in State College.

   Paul Dubin of Purdue University in W. Lafayette, Indiana, opened the symposium with a presentation on coacervation in mixtures of anionic/nonionic micelles or small colloids with polycations. These processes can stabilize or flocculate industrial dispersions, and pharmaceutical or cosmetic formulations, he explained.

   In another presentation, David Sabatini of the University of Oklahoma in Norman presented his recent work on cationic/anionic surfactant mixtures (Journal of Surfactants and Detergents 6: 215–224, 2003). The strong interactions between oppositely charged surfactants will lead to ultra-low critical micelle concentrations, increased surface activity, and the possibility of considerable cost savings in products containing surfactants, according to Sabatini. Unfortunately, these mixed systems tend to form intractable liquid crystals, or gels, rather than micellar or emulsion structures. The mesoscale morphology may be adjusted by adding alcohols, he said, but this may not be a practical solution for cost, environmental, or toxicity reasons. He proposed an alternative approach to using asymmetric surfactants.

   Ying Hu a graduate student from Princeton University in Princeton New Jersey, described new work in which an atomic force microscope tip clears nanoscale patches in a self-assembled monolayer of alkane thiols on gold. Protein helix bundles adsorbed onto the cleared patches may change the properties of the system as they specifically absorb small molecules, he said, creating a nanoscale biosensor array (Nano Letters 3: 425–429, 2003).    Industrial presenters focusing on particular applications included Srividya Ramakrishnan of Unilever Research, Edgewater, New Jersey, who reported on the effect of retinol and retinoic acid as well as anti-irritants such as borage seed oil on the organization of corneum lipids. David Osborne of Atrix Laboratories, Fort Collins, Colorado, reported on the ability of perfluorinated surfactants to enhance the skin permeation and percutaneous absorption of fluorinated drugs. His in vitro studies showed that transport of a fluorinated vitamin D analog or of fluocinonide across human cadaver skin was dramatically increased when perfluorinated surfactants were used.

   The ACS Colloid and Surface Science Division honored the 2003 Langmuir Lecturers John Polanyi of the University of Toronto in Canada and David Pine of the University of California in Santa Barbara at the division luncheon. Pine presented his work characterizing and designing self-assembled colloidal materials, including a new technique for making uniform macroporous materials using emulsions as templates. Potential applications include construction of crystals with photonic band gaps, he said. John Polanyi reported how he and his group could observe molecular reaction-dynamics using scanning tunneling microscopy as benzene, halobenzene and multiply-halogenated benzenes absorbed and desorbed or reacted on silicon surfaces. He compared the experimental findings with predictions from ab initio calculations.

   As in the past, modeling and computational chemistry were well represented, with a strong program by the Computer in Chemistry division (COMP) and symposia on modeling in several other divisional programs. Speaking in one of the COMP sessions, Ilia Siepmann of the University of Minnesota in Minneapolis described his continuing efforts to model complex systems such as surfactant solutions. His Monte Carlo methods are now able to predict nucleation phenomena, aggregation behavior, phase diagrams, and surface segregation for aqueous solutions of short chain alcohols (Journal of the American Chemical Society 124: 12232–12237, 2003).

   In a session based on the Industrial Fluid Properties Simulation Challenge, (http://www.cstl.nist.gov/FluidSimulationChallenge/) researchers debated different approaches for developing intermolecular potentials and predicting properties such as density, viscosity, and enthalpies of mixing. My own molecular modeling work, a study of Lauroyl ethylenediaminetriacetate (LED3A), was described by my former colleague, Tom Connors, of Colgate-Palmolive Co. in Piscataway, New Jersey, as part of his presentation on novel light-duty dishwashing liquid cleaning compositions.

   LED3A is a member of a new class of chelating surfactants that are analogues of ethylenediaminetetraacetate (EDTA) and in which one of the four acetate groups is replaced by an acyl group with a hydrocarbon tail. Interactions between LED3A surfactants, particularly under hard water conditions, are predicted to stabilize surfactant films resulting in the experimentally observed foam boasting properties of LED3A. LED3A also is predicted to form a complex with zinc ions enabling the creation of stable, transparent, antimicrobial, dishwashing liquid formulations, he noted.

   Elizabeth Piocos from The Procter and Gamble Co. in Cincinnati, Ohio organized a symposium on Innovations in Women’s Health and Products for the ACS Womens Chemistry Committee. The afternoon session of this well-attended symposium was particularly interesting as Shannon Campbell of Colgate-Palmolive Co. in Piscataway, New Jersey, and Paula Kemery of The Procter and Gamble Co., described the science behind new antiperspirant products for women. Market research suggests that women prefer antiperspirant sticks that do not leave a white residue, but they are not satisfied with clear products that have wet sticky application aesthetics. Shannon described how Colgate, through a joint venture with Dow Corning of Midland, Michigan, developed the first clear gellant for cyclomethicone that allows the antiperspirant to maintain a dry, silky feel on application.

   Kennery focused on the challenge of delivering pantothenic acid (vitamin B5) despite the relatively harsh chemical environment of an antiperspirant. Clinical studies have shown the protected form of the vitamin, panthenyl triactate, can be delivered to the skin where it is converted to the active form and provides significant improvement in skin condition for women suffering from skin irritation caused by shaving their underarm regions.

The tone of the meeting changed on the last day. ACS National Meetings are planned several years in advance, and there had been talk of changing the date or venue following the tragic events of September 11th 2001. The decision was made to continue the meeting, but to recognize the anniversary with a number of special presentations. Several attendees chose to mark the anniversary by visiting ground zero. We all walked quietly between the morning sessions as the names of the 9/11 victims, broadcast from the TV monitors, echoed around the open spaces of the Javits Center. It was an appropriately subdued conclusion to the 226th ACS National Meeting.

Fiona Case is a consultant and science journalist. She may be reached at fiona@casescientific.com or www.casescientific.com.