USING MONTE-CARLO SIMULATIONS AND SELF-CONSISTENT-FIELD THEORY TO DESIGN INTERFACIALLY ACTIVE COPOLYMERS

We use both Monte Carlo computer simulations and numerical self-consis tent field lattice calculations to determine the behavior of copolymer s at penetrable and impenetrable interfaces. These computational techn iques are useful as ''design tools'': they allow us to systemically va ry the copolymer architecture, determine optimal structures for specif ic applications, and establish guidelines for fabricating copolymers t hat yield the desired interfacial properties. We illustrate this princ iple with three different examples. In the first study, we combine the techniques to design copolymer compatibilizers that enhance the stren gth of immiscible polymer blends. These copolymers contain teeth that associate across the penetrable interface between the phase-separated regions and form a ''molecular velcro'' that effectively binds the reg ions together. In the case of impenetrable interfaces, we determine ho w the copolymer sequence distribution affects the structure of a layer of copolymers grafted onto a solid surface. The results indicate how to control the morphology of the layer and the surface properties of t he substrate, by varying the microstructure of the grafted copolymers. Finally, we design a polymer channel that ''opens'' and ''closes'' in response to changes in the pH and quality of the surrounding solvent. The channel is formed from polyacid chains that are anchored onto a s olid surface. Due to these properties, the system can be used for cont rolled release or sensor devices.