Self-assembled micelles based on branched poly(styrene-alt-maleic anhydride) as particulate emulsifiers

Abstract

Branched copolymer self-assembled micelles, based on amphiphilic branched poly(styrene-alt-maleic anhydride) (BPSMA) synthesized by a one-pot method, are prepared and employed as particulate emulsifiers to stabilize the white oil-in-water Pickering emulsions. The influences of micelle concentration, branching degree, salinity, and oil type on the emulsifying performance of self-assembled micelles are comprehensively investigated, and the distinction between BPSMA micelles and linear poly(styrene-alt-maleic anhydride) (LPSMA) self-assembled micelles on the micellar structure and emulsifying performance is also studied. The results show that the branched structure of the copolymer plays an important role in emulsification. The emulsifying performance of BPSMA micelles is superior to that of LPSMA micelles, reflected in the emulsifying efficiency and the long-term stability of emulsions. It is attributed to the much better structural stability of BPSMA micelles compared to LPSMA micelles, which is probably due to the postponing of hydrolyzing of maleic anhydride and ionization of carboxyl to some extent caused by the introduction of the branched structure in copolymers. It is also worth noting that, salinity has a great effect on the emulsifying performance of LPSMA micelles, but little impact on that of BPSMA micelles. Additionally, BPSMA micelles can also well stabilize the oil-in-water emulsions with some other types of natural oils. Thus the findings are not only of theoretical interest but also of great practical application in the cosmetics area.