Impressed pressure-facilitated seeded emulsion polymerization: design of fast swelling strategies for massive fabrication of patchy microparticles

It is well-documented that traditional seeded emulsion polymerization (SEP) is not only a simple, universal and large-scale method, but also a time-consuming procedure. This is the main constraint of SEP in terms of economy or sustainable development. In this study, pressure-facilitated SEP (high-pressure swelling and ultrasound swelling polymerization) were designed and developed for the first time to accelerate the seed swelling process. According to these two strategies, swelling equilibrium can be realized quickly in several minutes. Meanwhile, dimpled swollen particles with different sizes of single hole were formed. When polymerization of swollen seed emulsion was initiated, PGMA/PS patchy microparticles with a controlled shape were synthesized. Moreover, the morphological evolution of these microparticles was precisely controlled by the swelling time and DBP/S ratios. Both high-pressure and ultrasound swelling polymerization not only promote the fast and large-scale fabrication of patchy particles for potential applications, but also decrease the production cost and increase the efficiency of SEP.