Synthesis and Applications of Elastomeric Polymerized High Internal Phase Emulsions (PolyHIPEs)

Abstract

Polymer foams (PFs) are among the most industrially produced polymeric materials, and they are found in applications including aerospace, packaging, textiles, and biomaterials. PFs are predominantly prepared using gas-blowing techniques, but PFs can also be prepared from templating techniques such as polymerized high internal phase emulsions (polyHIPEs). PolyHIPEs have many experimental design variables which control the physical, mechanical, and chemical properties of the resulting PFs. Both rigid and elastic polyHIPEs can be prepared, but while elastomeric polyHIPEs are less commonly reported than hard polyHIPEs, elastomeric polyHIPEs are instrumental in the realization of new materials in applications including flexible separation membranes, energy storage in soft robotics, and 3D-printed soft tissue engineering scaffolds. Furthermore, there are few limitations to the types of polymers and polymerization methods that have been used to prepare elastic polyHIPEs due to the wide range of polymerization conditions that are compatible with the polyHIPE method. In this review, an overview of the chemistry used to prepare elastic polyHIPEs from early reports to modern polymerization methods is provided, focusing on the applications that flexible polyHIPEs are used in. The review consists of four sections organized around polymer classes used in the preparation of polyHIPEs: (meth)acrylics and (meth)acrylamides, silicones, polyesters and polyurethanes, and naturally occurring polymers. Within each section, the common properties, current challenges, and an outlook is suggested on where elastomeric polyHIPEs can be expected to continue to make broad, positive impacts on materials and technology for the future.

Unique Crystallization Characteristics of Pickering High Internal Phase Emulsion Templated Porous Constructs

“…HIPEs were conventionally developed from aqueous emulsions utilizing free radical polymerization of vinylic monomers; therefore, the use of water-sensitive polymerization techniques or high temperatures was severely restricted until now. The introduction of oil-in-oil nonaqueous HIPEs overcame these major restrains of conventional systems. − Over the years, polyHIPEs have been fabricated using a wide range of polymers and various polymerization techniques including free radical polymerization, atom transfer radical polymerization, reversible addition–fragmentation chain transfer, and ring-opening polymerization (ROP), etc . Further, various studies indicating the influence of polyHIPE composition on material properties like mechanical strength, liquid uptake capacity, thermal behavior, biodegradation, etc., have been reported.…”

Ring-opening polymerization of emulsion-templated deep eutectic system monomer for macroporous polyesters with controlled degradability

“…Macroporous polymers have found widespread use in various advanced applications, such as biomaterials, 1 tissue engineering scaffolds, 2,3 separation membranes, 4 energy storage, 5 and substrates facilitating specific surface-related phenomena. 6,7 These applications stem from the enlarged surface area and the three-dimensional arrangement of interconnected pores, which enable efficient mass transport and specialized interfaces for reactions and interactions with target molecules.…”