PDMS polymerized high internal phase emulsions (polyHIPEs) with closed-cell, aqueous-filled microcavities

Area of Science:

• Materials Science
• Biomaterials Engineering
• Polymer Chemistry

Background:

• Emulsion templates enable unique microstructures for fluid-filled composites.
• Current materials lack biocompatibility, mechanical robustness, and systematic processing for mimicking biological tissues.
• Polydimethylsiloxane (PDMS) offers potential for advanced elastomeric foams.

Purpose of the Study:

• To synthesize high internal phase, closed-cell PDMS elastomeric foams with enhanced properties.
• To achieve biocompatibility, mechanical robustness, flexibility, and selective permeability in PDMS foams.
• To establish systematic processing parameters for creating these advanced composites.

Main Methods:

• Utilized water-in-oil high internal phase emulsions (HIPEs) stabilized by silica nanoparticles (SNPs) as templates.
• Overcame high viscosity challenges by employing centrifugation of low internal phase emulsions (LIPEs).
• Systematically characterized microstructural dependence on viscosity ratio, mixing speed, emulsifier concentration, and centrifugal force.

Main Results:

• Synthesized PDMS elastomeric foams with >74% aqueous phase (up to 82%).
• Achieved fluid-filled, closed-cell structures with excellent mechanical robustness and flexibility.
• Demonstrated control over microstructure via systematic characterization of processing parameters.

Conclusions:

• Developed a novel method for creating biocompatible, mechanically robust, and flexible PDMS elastomeric foams.
• The synthesized foams show promise for applications requiring tissue-like mechanical and functional properties.
• This work provides a systematic approach to processing advanced microstructured, fluid-filled elastomer composites.