Dynamic and Nonequilibrium Aspects of Polymer Adsorption

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The adsorption of macromolecules at interfaces of materials plays a key role in many of today's critical technologies. Many advanced materials rely heavily on the effects of polymer adsorption. For example. impact resistant polymer blends for automotive applications and multilayer film laminates for "smart" barriers and imaging technologies enjoy dramatically improved performance and/or processibility when the interfacial regions are modified by polymer adsorption. Materials technologies relying on colloidal suspensions (e.g. coating processes and "slip-casting" for ceramics manufacture) utilize polymer adsorption for crucial improvement in suspensions properties. Polymer adsorption also plays a key role in biomedicine. For example, the adsorption of blood proteins is a key issue in developing protheses, blood- contacting devices and drug-delivery systems. In the separations field, adsorption chromatography, which relies on competitive adsorption, is the most effective means of separating subtly different macromolecules. The dynamic and nonequilibrium aspects of polymer adsorption are largely unexplored. The principal goal of this work is to study these aspects in model materials (linear homopolymers and diblock copolymers on dielectric and metal surfaces) using a quartz microbalance, ESR, and fluorescence spectroscopies and pattern photobleacing. These methods will probe elementary dynamic phenomenal in adsorbed layers and will clarify the mechanisms of adsorption. The results will provide a basis for controlling adsorption processes crucial in application. The project involves close collaboration between the Department of Chemical Engineering and Chemistry at Columbia University.