All‐Dry Fabrication of Poly(methacrylic acid)‐Based Membranes with Controlled Dissolution Behavior

Abstract

The all-dry fabrication of porous poly(methacrylic acid)-based membranes displaying tunable dissolution behaviors in aqueous media is presented. Poly(methacrylic acid) (PMAA) membranes were fabricated using a low temperature, solventless technique with gaseous initiator and monomer precursors. The PMAA was then converted to poly(methacrylic acid-co-methacrylic anhydride) by thermal annealing. By controlling the annealing time, the methacrylic anhydride (MAN) content was varied, which allowed for the dissolution behavior to be tuned. The incorporation of MAN moieties in the membranes also allowed for crosslinking via a vapor phase reaction with 1,3-diaminopropane. The membranes can be deposited on a variety of substrates, including gauze.

Vapor Phase Fabrication of Hydrophilic and Hydrophobic Asymmetric Polymer Membranes

“…After the depositions, the membranes were placed in an oven to convert the PMAA to P(MAA‐ co ‐MAN). Some of the methacrylic acid moieties convert into methacrylic anhydride moieties through an annealing process that causes the elimination of water, which results in the formation of anhydrides between adjacent pairs of carboxylic acid groups . In order to increase the long‐term stability of P(MAA‐ co ‐MAN), the membranes were further exposed to DAP vapor.…”

“…Some of the methacrylic acid moieties convert into methacrylic anhydride moieties through an annealing process that causes the elimination of water, which results in the formation of anhydrides between adjacent pairs of carboxylic acid groups. [ 30 ] In order to increase the long-term stability of P(MAA-co -MAN), the membranes were further exposed to DAP vapor. DAP is a difunctional amine molecule which can react with the methacrylic anhydride linkages to permanently cross-link the polymer in order to make the membranes insoluble.…”

Downstream Monomer Capture and Polymerization during Vapor Phase Fabrication of Porous Membranes

“…The monomer adsorbs to the surface of the substrate, which is usually kept at room temperature, and polymerization occurs via a free radical mechanism, leading to the formation of a dense film. Our group has recently modified the iCVD process to fabricate polymer membranes with dual scale porosity by maintaining the monomer partial pressure and the substrate temperature below the triple point pressure and temperature of the monomer using a thermoelectric cooler (TEC). − At these unconventional conditions, the monomer deposits as solid microstructures. Polymerization occurs at both the vapor–solid interface and within the solid structure and the excess unreacted monomer is subsequently sublimated. − There is no unreacted monomer in the final polymer membranes as confirmed by Fourier-transform infrared spectroscopy analysis .…”

Giant Lipid Vesicle Formation Using Vapor-Deposited Charged Porous Polymers

“…In this study, our modified iCVD technique was used to form porous polymer membranes by introducing the gaseous monomer into a vacuum chamber, where the monomer partial pressure and substrate temperature are kept below the triple-point pressure and freezing temperature of the monomer. Hence, the vapor undergoes a gas- to solid-phase change on the surface of the substrate and forms solid microstructures. − Polymerization subsequently occurs under a heated filament array in the presence of an initiator, and a cross-linking agent is used to render the polymer insoluble in aqueous media . Following polymerization, unreacted solid monomer is removed via sublimation, resulting in membranes with dual-scale porosity.…”