(809b) Porous Polymer Membranes By Simultaneous Polymerization and Solid Monomer Deposition

Here we demonstrate a novel technique for the fabrication of porous polymer membranes by vapor phase polymerization.¹ Traditionally, vapor phase polymerization is used to create conformal nonporous polymer films on a wide range of substrates by eliminating the solubility requirements and surface tension effects which occur in the solution phase.² In our talk, we will show that we can use nontraditional processing conditions to make robust, functional polymer membranes. Our process requires concurrent monomer deposition and polymerization, which is achieved by keeping the monomer partial pressure above its saturation pressure and the substrate temperature below the freezing point of the monomer.  The resulting membranes exhibit dual-scale porosity, where large-scale pores form during the deposition and small-scale pores form upon sublimation of the solid monomer. Control over the growth rate and pore size is possible by varying the reactor parameters, including deposition time, monomer partial pressure, and substrate temperature. We will demonstrate that our unique process can be used to fabricate stimuli-responsive poly(methacrylic acid) and poly(N-isopropylacrylamide) membranes. Furthermore, multiple precursors can be used to make copolymer membranes, as we demonstrate by using ethylene glycol diacrylate as a cross-linking agent. Our unconventional processing conditions represent an untapped area of study and have the potential to produce tailored polymer membranes with diverse functionalities for applications in filtration and biosensing.

References:

1)      Seidel, S.; Kwong, P.; Gupta, M. Simultaneous Polymerization and Solid Monomer Deposition for the Fabrication of Polymer Membranes with Dual-Scale Porosity. Macromolecules 2013, 46, 2976-2983.

2)      Seidel, S.; Riche, C.; Gupta, M. Chemical Vapor Deposition of Polymer Films. Encycl. Polym. Sci. and Technol. 2011.