- 9:20 AM

Diffusion and Interfacial Behavior of PDMS-Water Systems

Ahmed E. Ismail, Performance Assessment and Decisions Analysis Department, Sandia National Laboratories, 4100 National Parks Hwy, Carlsbad, NM 88220, Gary S. Grest, Surface and Interface Sciences, Sandia National Laboratories, PO Box 5800, MS 1395, Albuquerque, NM 87185-1395, David R. Heine, Science and Technology Division, Corning, Inc., SP-TD-01-1, Corning, NY 14831, Mark J. Stevens, Sandia National Laboratories, MS 1411, Albuquerque, NM 87185-1411, and Mesfin Tsige, Dept. of Physics, Southern Illinois University at Carbondale, Mail Code 4401, Carbondale, IL 62901.

Polydimethylsiloxane (PDMS) is a main constituent of silicone adhesives, which have a wide use as adhesives. Often these adhesives are used as sealants. The interaction between water and PDMS is of fundamental importance. To improve our understanding at the molecular level, we have performed molecular dynamics (MD) simulations of PDMS in the presence of water, with the long-term goal of studying how water molecules effect debonding at the surface. Knowledge of the basic interfacial properties of a multicomponent system, such as the surface tension, contact angle, and diffusion constant, are essential to obtain the proper dynamic behavior in a molecular simulation of adhesion and wetting processes. Explicit-atom simulations have been used to study the structure and dynamics of the PDMS-water interface and of water diffusing through bulk PDMS. In particular, we focus on the effects of temperature and concentration dependence.