Carbon Dioxide Switchable Polymers and Processes in Polymer Reaction Engineering

摘要

We have prepared a variety of polymer nanoparticles with surface properties that can be switched from charged to uncharged using only carbon dioxide and air as triggers. Our initial approach to designing these materials relied on using pre-made "switchable surfactants" via emulsion polymerization. This approach is similar to that employed to make the majority of polymer latexes used in commercial applications. We then refined the process further to address a shortcoming of many emulsion polymers, that of surfactant migration due to the stabilizing species not being covalently bound, by developing variants of surfactant free processes for making carbon dioxide switchable polymer colloids: (1) using only a carbon dioxide switchable initiator; (2) using a carbon dioxide switchable comonomer which is copolymerized in situ to generate the stabilizing species; and (3) using living radical polymerization to prepare nanoparticles via a Polymerization Induced Self Assembly (PISA) process. In all of these cases, the stabilizing moieties are covalently bound to the particle surface.