Functional Polymer Surfaces

Virginia Commonwealth University, Richmond VA

Investigators

Abstract

This research is aimed at generating functional polymer surfaces with compositional economy, new or improved properties, and facile, conventional processing. One research thrust focuses on P[AB] (co-polyoxetane) soft block polyurethanes as minor constituents (2 wt% or less) in blends such that the co-polyoxetane soft block defines surface properties while the base polymer defines bulk properties. A unique feature is synergistic interactions of A and B co-repeats that produce new surface phenomena. Prior research points to opportunities via increasing the mole fraction charged (quaternary) B co-repeat units in P[AB]-soft block polyurethanes. This strategy is aimed at facilitating physical studies of surface concentration and accelerating kinetics of antimicrobial action. Newly discovered "seeding" of layer by layer (LbL) processing via polycationic modifiers will be explored as a method to quickly and radically change surface properties. Other P[AB]-soft block polyurethanes that confer "contraphilic" wetting will be studied as these surfaces may have unique biocompatibility. The structure and surface dynamics of new semicrystalline fluorous polyoxetanes will be evaluated as promising candidates for environmentally responsible hydrophobic/oleophobic coatings. Finally, modifying condensation cured polydimethylsiloxane networks by a recently discovered approach is aimed at introducing oleophobicity and surface concentration of quaternary charge. NON-TECHNICAL SUMMARY: Polymer surfaces are encountered in a myriad of everyday things such as painted or coated surfaces and molded objects. This research is aimed at economically introducing special functions into such surfaces. One subject is generation of durable, intrinsically sterile surfaces in an economical way. The special function of sterility (with economy) is needed for healthcare facilities to thwart the spread of disease. To achieve these and other desirable surface characteristics, special additives are designed for conventional coatings such that a very small amount spontaneously concentrates at the surface during conventional application. Another surface function being developed is a novel wetting characteristic that is counterintuitive: a surface that is initially "water loving" but becomes resistant to wetting after the surface is initially wetted. Such a wetting property looks promising for medical device coatings that require compatibility with body tissue or fluids. Broader impacts of this research include interdisciplinary training in chemistry, surface science and microbiology, which results in high demand for students and postdoctoral scientists by companies such as contact lens producers and companies employing biotechnology for drug manufacture. This research is aimed at effecting broader impacts locally, through undergraduate and graduate course development (e.g., the course "Introduction to Polymers in Medicine") and through underrepresented minority participation in research. On a national level, support for this research facilitates leadership activities such as co-organization of the biennial American Chemical Society K-12 workshops / symposia "Polymer Science of Everyday Things". International collaborative work and student exchange with groups in Japan, Italy, and Sweden play a vital role in understanding how the targeted surfaces are modified.