Investigation of defects on PAMS microspheres fabricated with microencapsulation method

Poly-(-methylstyrene) (PAMS) microspheres were fabricated with W1/O/W2 double emulsion microencapsulation method,and the effects of polyvinylalcohol (PVA) and CaCl2 weight concentrations and the O/W2 phase ratio on the percentages of defected PAMS microspheres were studied. The weight concentrations of PVA and CaCl2 and the O/W2 phase ratio in the fabrication process of PAMS microspheres were optimized. The results show that, for the three parameters being 1.0%, 1.5%, and 0.01, respectively, the percentage of the defect-free PAMS microspheres without vacuoles in the shell wall can be up to 60%.