Preparation hollow like polymer particle via swollen polystyrene seed particle

Micron-sized monodispersed cross-linked polymer particles having a single hollow in the inside were produced by seeded polymerization for the dispersion of (toluene/ethylene glycol dimethacrylate)-swollen polystyrene (PS) particles prepared utilizing the dynamic swelling method .In this article, the particles at various conversions of the seeded polymerization were observed with an optical and SEM microscope in detail. From the obtained results, the formation mechanism of the hollow structure is suggested as follows. As seeded polymerization proceeds, polyethylene glycol dimethacrylate (PEGDMA) molecules precipitated in the swollen particle are trapped near the interface and gradually pile at the inner surface ,which results in a cross-linked PEGDMA shell. PS which dissolves in theswollen particles is repelled gradually to the inside. After the completion of the polymerization, toluene in the hollow evaporates by drying, and PS clings to the inner wall of the shell uniformly