Designer, reactive polydopamine primers for surface engineering

Polymers have been engineered to provide exact properties in the bulk for many different applications. The surface properties, however, tend to lack behind, requiring costly and complicated procedures to bring them up to par. In nature, there exists a group of creatures that can adhere themselves to many substrates independent of material composition in challenging environments. Catechol and amine chemistry lie at the basis of the adhesion of these marine organisms. These adhesion capabilities have been applied in a biomimetic system called polydopamine (PDA). PDAs and PDA based materials have been developed and applied on many different surfaces ranging from stainless steel and titanium to polyethylene other polyolefins, and even poly(tetrafluoroethylene). This makes PDAs excellent candidates for developing a universal primer for surface functionalization. In this thesis, a PDA-based polymer macro-initiator is developed for grafting from a surface using surface polymerization or grafting to a surface using click chemistry. These ingredients have provided a platform through which a variety of substrates, from silicon wafers to poly(tetrafluoroethylene), have been successfully functionalized. The optimal composition of the copolymer has been determined for functionalized layer thickness and stability and layer thickness have been improved through thermal treatment as well as crosslinking using both cationic and covalent linkers. These layers have been functionalized using Surface-Initiated Atom Transfer Radical Polymerization with poly(oligoethylene glycol)methacrylate and zwitterionic sulfobetaine layers to provide antifouling surfaces on PE. Click chemistry is used to attach a fluorescent rhodamine dye for photonic engineering as well as chitosan for a different pathway to obtain antifouling functionality. Functionality can also be included in such a PDA-based copolymer system as demonstrated using a poly(N-isopropyl acrylamide)-b-poly(dopamine methacrylamide) polymer for atmospheric water harvesting on plant leaves. These showcases demonstrate both the viability for these PDA-based materials as a platform for functionality as well as its strength in adhering to different types of surfaces.