Conformations and Dynamics of Polymers at Interfaces

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9316157 Rafailovich Recently, several research groups have demonstrated that due to the large entropy associated with confining long polymer molecules at interfaces, the classical wetting theories developed for simple liquids do not apply. I order to obtain a better understanding of the wetting properties of polymer films we are employing a variety of complementary techniques (SIMS, reflectivity, TEM, and AFM) to conduct an three-fold program. 1) Wetting properties of thin liquid polymer films: We are exploring the role of the chain dimensions on the film stability, surface diffusion, glass transition, wetting of rough surfaces, and total density. Modification of mean-field theories to include new experimental phenomena are being developed. 2) Surface modification via end- functionalized polymers: The conformations of end-grafted polymers are being studied both in melts and solutions under steady-state shear. The in-plane structure of brushes is being studied and compared with theoretical simulations. 3) Surface induced ordering of triblock copolymers: Triblock copolymers have the unique ability to form surface-induced micelle gel films. We are studying the penetration and wetting of homopolymer films on these gel surfaces as a function of the relative molecular weights of the two components and the interaction energies with the ordering surface. Very thin polymer films are known to have a large variety of applications such as lubricants, coatings for optical and electronic components, and adhesives. In order for these films to be effective, they must wet the surfaces upon which they are spread or penetrate through the interfaces to provide adhesive strength. ***