UC Santa Barbara
Fabrication of Polymer Brushes via Light-Mediated Polymerization and Polymerization of Acrylic Acid
- Author(s): Narupai, Benjaporn
- Advisor(s): Hawker, Craig J.
- et al.
The development of polymer synthesis is of great significance towards the preparation of functional materials. Polymers have been used in surface modifications ranging from antifouling, antifogging to chemical sensing. Surfaces are often modified by a variety of techniques such as spin-coating, painting or dipping. However, these physisorption techniques lack stability against erosion. Covalent chemical attachment overcomes this disadvantage and offers chemical robustness with synthetic flexibility. Surface-initiated polymerizations are one of the most efficient strategies to modify surface properties via covalent attachment while providing high grafting density of a variety of functional groups as well as the ability to pattern the surfaces. This dissertation will highlight the development of three synthetic strategies. First, a novel strategy to synthesize branched polymer brushes by sequential light-mediated polymerization is demonstrated. Stepwise synthesis including linear copolymerization, deactivation of active chain ends and secondary graft polymerization is described affording branched polymer brush architectures. Secondly, the fabrication of well-defined, multifunctional polymer brushes using microliter volumes under ambient conditions is reported. This simple synthetic strategy uses photoinduced polymerization with metal-free photoredox catalyst which acts as both an oxygen scavenger and polymerization catalyst. Finally, the rapid copolymerization of acrylic acid and sodium acrylate is demonstrated. This polymerization uses an alkyl iodide/sodium iodide as a mediator in water affording copolymers with a moderate control over molecular weight and dispersity.