Novel Polymer Thin Film Process Using Supercritical Carbon Dioxide as an Environmentally Green Solvent

Abstract

The utilization of supercritical fluids (SCFs) has recently become prominent in a number of polymer processes such as inducing the ordering of block copolymer templates, synthesizing nanoporous material, and spatially distributing nanoparticles in a matrix. For such processes, conventional techniques have relied heavily on the use of toxic organic solvents such as chloroform and toluene. In contrast, certain SCFs, such as supercritical carbon dioxide (scCO2), have been distinguished as a "green" alternative because they are nontoxic, nonflammable, and inexpensive. Furthermore, the easily attainable critical temperature and pressure (Tc=31.3 ??C and Pc=7.38 MPa, respectively) make it an ideal solvent choice for polymers that degrade at low temperatures. In the following, I describe the research characterizing the effects of scCO2 on polymer thin films and brushes, specifically their swollen structures. This was achieved using multiple tools including, Neutron Reflectivity, X-Ray Scattering, and various microscopy techniques. I also present and recommend on-going and future work.