Deformation of raspberry-like polymer composite particles by colloidal fusion†
Colloidal fusion is an emerging method to fabricate core–shell colloidal particles. This work aims to investigate the feasibility of deforming raspberry-like polymer composite particles with polymer coronas by colloidal fusion. Two types of raspberry-like polymer composite particles prepared by seeded emulsion polymerization were attempted. One was submicrometer-sized silica–polystyrene (SiO2–PS) composite particles and another one was micrometer-sized poly(glycidyl methacrylate)–polystyrene (PGMA–PS) composite particles. Initial melting experiments based on submicrometer-sized SiO2–PS composite particles were less successful. SiO2–PS composite particles with ill-defined core–shell morphologies were fabricated by melting the raspberry-like composite particles in a THF/ethanol medium within 20 s. The effects of different melting parameters including the THF concentration, composite particle concentration, agitation rate and agitation time on the morphology of the composite particles were investigated, which suggested that the level of deformation was mainly affected by the THF concentration. On the other hand, the melting experiments based on micrometer-sized PGMA–PS composite particles in THF/water medium could lead to a well-defined core–shell morphology. The influence of the THF concentration on the morphology of the composite particles was also studied, which indicated that the surface roughness of the composite particles could be easily tuned by varying the THF concentration.