Synthesis of patterned polyHIPE-hydrogel composite materials using thiol-ene chemistry

Polydimethylsiloxane Polymerized Emulsions for Acoustic Materials Prepared Using Reactive Triblock Copolymer Surfactants

“…In contrast, polyMIPEs prepared from Silube show significant pore collapse at porosities over 60% with Φ exp ∼20% lower than the expected theoretical value due to pore collapse when an emulsion template with 75% IP volume fraction was used. Similar pore collapse has been observed in our previous work , and work from others with soft, porous materials made from polymers with low glass-transition temperatures. The observed pore collapse is typically caused by capillary forces experienced during the drying process as the internal phase is removed from the porous material.…”

“…Specifically, emulsions consisting of an IP volume fraction >74% are called polyHIPEs, while emulsions having an IP volume fraction between 74 and 25% are called medium internal phase emulsions (polyMIPEs), and emulsions with <24% IP are called low internal phase emulsions (polyLIPEs), respectively. Emulsion-templated polymers made using low glass-transition temperature elastomers, including PDMS can suffer from collapse of the pore structure at porosity values over ∼60%. , Methods such as the use of super critical CO 2 drying or the addition of internal blowing agents such as peroxides have used to try to overcome this challenge, ,, and recently our group has shown that increasing the cross-linking density of the PDMS network is a simple route to achieve polyHIPEs having a porosity of 77% under standard drying conditions and without additives …”

“…Previously, we reported PDMS-based acoustic materials prepared from thiol- and ene-functionalized PDMSs using polymerized emulsion templating methods that obtain low C L values of ∼40–50 m/s. , In these reports, the thiol to ene ratio was varied to adjust the mechanical properties, and we were able to obtain materials with moduli differences of ∼200 kPa at a single porosity. We used the commercially available surfactant “Silube” to stabilize the emulsions in our previous work, and we were consequently limited to a single pore morphology in the final polymerized materials.…”

“…Emulsion-templated polymers made using low glass-transition temperature elastomers, including PDMS can suffer from collapse of the pore structure at porosity values over ∼60%. 34,35 Methods such as the use of super critical CO 2 drying or the addition of internal blowing agents such as peroxides have used to try to overcome this challenge, 19,20,25 and recently our group has shown that increasing the crosslinking density of the PDMS network is a simple route to achieve polyHIPEs having a porosity of 77% under standard drying conditions and without additives. 28 The pore morphology of porous polymer materials can play a significant role in the materials' mechanical properties.…”