Porous elastomeric polymers have been used in a wide range of applications due to their unique characteristics such as biocompatibility, gas permeability, thermal stability, and hydrophobic and dielectric properties. Poly(dimethyl siloxane) (PDMS), a commercially available elastomer, has also been shown to exhibit specific acoustic properties. However, the materials properties were limited due to a lack of control over the chemistry used to prepare the crosslinked PDMS elastomer. Here, the synthesis of PDMS-based polymerized medium internal phase emulsions (polyMIPEs) with tunable storage shear moduli (G') have been prepared using macromolecular thiol-ene reactions. Storage shear moduli values from ~38 to ~330 kPa were achieved by changing the stoichiometric ratio of the thiol-to ene-functionalized PDMS whereas the porosity of the polyMIPEs was controlled by the volume of aqueous phase used in the emulsion formulation. Very low sound velocities (~40 m/s) through the porous materials were recorded using acoustic characterization. Therefore, this work provides an example of the synthesis of soft polyMIPEs with possible applications as acoustic materials.

Shape memory polymers (SMPs) are a class of responsive polymers that have attracted attention in designing biomedical devices because of their potential to improve minimally invasive surgeries. Use of porous SMPs in vascular grafts has been proposed because porosity aids in transfer of fluids through the graft and growth of vascular tissue. However, porosity also allows blood to leak through grafts so preclotting the materials is necessary. Here hydrogels have been synthesized from acrylic acid and N‐hydroxyethyl acrylamide and coated around a porous SMP produced from lactose functionalized polyurea‐urethanes. The biocompatibility of the polymers used to prepare the cross‐linked shape memory material is demonstrated using an in vitro cell assay. As expected, the hydrogel coating enhanced fluid uptake abilities without hindering the shape memory properties. These results indicate that hydrogels can be used in porous SMP materials without inhibiting the shape recovery of the material. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1389–1395

Porous PDMS elastomers were synthesized using emulsion templated thiol–ene “click” reactions to obtain materials with tunable storage moduli at a single porosity value that achieve low sound speed values of ∼40 m s−1.

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