Covalent layer-by-layer assembly of reactive thin films fabricated from poly(2-alkenyl azlactone)s

The work described in this thesis focuses on the layer-by-layer fabrication and characterization of reactive polymer thin films assembled using azlactone-functionalized polymers. This research aims to develop methods and materials for the rapid fabrication and subsequent chemical modification of reactive thin films and provide a basis for general and versatile strategies that can be used to tailor the physicochemical properties of a broad range of surfaces and interfaces. The results presented here demonstrate that the azlactone-functionalized polymer poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) can be alternately deposited on surfaces or at interfaces with the primary amine-containing polymer branched poly(ethyleneimine) (PEI) to fabricate covalently crosslinked and reactive ultrathin films. Film assembly is driven by fast, interfacial chemical reactions between pendant azlactone functionality on PVDMA and primary amine groups of PEI. Films can be assembled on a variety of different solid substrates, including planar silicon, glass, polymer, or metallic substrates, or on topologically-complex substrates (e.g., fibers, fabrics). In addition to substrate-supported films, suspended, covalently crosslinked membranes can be assembled by using liquid/liquid interfaces created between immiscible aqueous and organic phases as templates for film fabrication. Flexible and reactive freestanding PEI/PVDMA thin films can also be obtained by delaminating films from glass or silicon substrates under mildly acidic conditions.;Residual azlactone functionality within these thin films can be exploited post- fabrication to tailor the physicochemical properties of these materials by reaction with a wide range of amine-containing nucleophiles. Results of experiments using chemical motifs known to prevent the adhesion of proteins and cells on other surfaces demonstrate that PEI/PVDMA films treated with these motifs resist the growth and proliferation of mammalian cells for at least one month in culture. These films can also be modified and patterned with a broad range of other chemical and biological functionality (e.g., hydrophobic or hydrophilic amines, peptides, proteins, etc.) to tailor the properties of film- coated substrates. The results presented in this thesis suggest the basis of a versatile approach to the functionalization of surfaces and interfaces and suggest opportunities to design crosslinked, chemically reactive thin films and membranes of interest in the contexts of catalysis, medicine, or other broad areas of biotechnology.