Effects of SiO2 particle surface design on the photocuring properties of interparticle photo-cross-linkable Pickering emulsions

Abstract

This study aims to investigate the effects of particle surface structures of interparticle photo-cross-linkable w/o Pickering emulsions, designed for the rapid manufacturing of porous ceramic components, on their microstructures, light-curing behaviors, and moldability. The emulsions were designed by mixing SiO2/toluene suspensions stabilized by functional polyethyleneimine (PEI), which was partially complexed with oleic acid (OA) in various ratios (15–50 mol% to total EI units), small quantities of multifunctional acrylate (MA), photo-radical initiator, and water. When the OA content was low (15 mol%), a Pickering emulsion was produced that had a lower size distribution of the dispersed phase than the emulsions obtained when the OA content was high. Additionally, the successful shaping of porous SiO2 bodies by in-situ photocuring of the Pickering emulsion in a silicone mold followed by drying was achieved when the OA content was low. However, severe structural collapse of photocured bodies was observed during drying when the OA content was high (30 and 50 mol%). The higher quantities of reactive amines present on the particle surface played an important role in ensuring interparticle photo-cross-linking, maintaining the structure of photocured bodies against capillary forces during drying.