Structural and mechanical impact of synthetic clay in composite foams made via high‐internal phase emulsions

Abstract Impacts of organophilic clay on open cell foams created from high‐internal phase emulsion templating were explored. Improving mechanical properties such as compression modulus by fillers is typically most challenging to realize. We investigated the effect of two different fillers: synthetic hectorite organophilized with a custom‐made organo‐cation and commercial organophilic montmorillonite. Contrary to the montmorillonite, the hectorite could significantly improve the foam mechanics, up to four times for foams with a relative density of 4.1%. Investigation of bulk mechanics and the morphology of foams led to the conclusion that the foam mechanics improvement is not due to a reinforcement of the struts. Instead, the organophilic hectorite might act as a Pickering emulsifier in addition to the molecular surfactants to achieve a more consistent structure, which in particular possesses more uniform strut thickness and improved mechanical properties.