CO2-Responsive Surfaces

Abstract

Designing smart materials with green chemistry in mind is a common theme throughout this thesis. Smart surfaces, i.e. a surface that can perform multiple tasks as a function of an external stimulus, have the potential to reduce waste by simplifying processes, reducing solvent use, and extending the lifetime of materials through simple regenerative procedures. The work presented in this thesis focuses on the development of CO2-responsive smart surfaces for green applications. CO2-responsive smart surfaces have been used as desiccants for the removal of water from organic solvents. For the first time, CO2-responsive smart desiccants were able to remove more water and were regenerated at a lower energy cost than traditional recyclable desiccants such as molecular sieves. Additionally, CO2-responsive smart surfaces were demonstrated to be smart supports for heterogeneous catalysis with ruthenium nanoparticles by allowing reversible changes in catalyst selectivity for the hydrogenation of furfural. In both applications, the CO2-responsive smart materials were recycled multiple times with little to no loss in performance. CO2-responsive smart materials were demonstrated to selectively capture and release hydrophobic liquids and dyes without loss of performance over time. A variety of substrates were evaluated as CO2-switchable surfaces using both single-unit and polymeric modifiers. A robust and user-friendly method for “surface-initiated activators generated by electron transfer atom transfer radical polymerization” (SI-AGET-ATRP) is described. The SI-AGET-ATRP technique is compatible with various CO2-responsive polymers and will allow future work to study topics of interest such as the relationships between grafting density, molecular weight, and material performance.