One-step fabrication of multihollow polystyrene particles from miniemulsion system with nonionic surfactant

This paper presented a new facile approach to fabricate polystyrene (PS) multihollow particles from miniemulsion polymerization. The surfactant used in this miniemulsion system was OP-10, a nonionic surfactant of nonyl phenyl polyoxyethylene with an average of 10 ethylene oxide units per molecule (hydrophilic-lipophilic balance, HLB = 13.9). Due to the partition characteristic of OP-10 in miniemulsion, W/O/W structured monomer droplets could be formed after ultrasonic dispersion. Under irradiation by gamma-ray, styrene polymerized through a droplet nucleation mechanism, which was the feature of miniemulsion polymerization. The formation of multihollow structure was affected by the content of OP-10 (W-OP) and pre-added PS (W-PS). It was found that when W-OP was above 2 wt% and W-PS was in the region of 2-10 wt% based on the monomer, multihollow PS particles could be obtained. The molecular weight of the PS latex particles synthesized was determined to be 10(5) g/mol by GPC. (C) 2008 Elsevier Ltd. All rights reserved.