Solvent polarity-mediated seeded swelling photo-initiated polymerization: Controlled preparation of Janus particles

Abstract

Traditional seeded emulsion polymerization is flexible and effective, but is time-consuming and labor-intensive. Therefore, developing simple and time-saving synthesis strategies still requires continuous exploration. Herein, solvent polarity-mediated seeded swelling photo-initiated polymerization strategy was proposed, which could realize rapid preparation of Janus particles. Additionally, by controlling the polarity of solvent (porogenic agent), it is possible to simultaneously prepare three types of Janus particles with both asymmetric morphology and chemical environment (dual Janus particles), with only structural asymmetry, or with only chemical environment asymmetry. Interestingly, when alkane alcohols were applied as polar solvents, increasing the carbon chain length (which gradually decreases polarity) results in a transition in particle morphology from spherical particles to Janus particles with only chemical environmental asymmetry, and then to dual Janus particles. However, when benzene series were utilized as non-polar solvent, the particles morphology changed from spherical particles to Janus particles with only structural asymmetry as the number of methyl groups on the benzene ring increases. Additionally, these particles can be easily modified to create amphiphilic particles, which have broad application prospects in emulsifying oil–water mixtures.