Hybrid amphiphilic block copolymers containing polyhedral oligomeric silsesquioxane: Synthesis, characterization, and self-assembly in solutions

In this article, the amphiphilic block copolymers containing polyhedral oligomeric silsesquioxane (POSS), namely PMAPOSS-b-PAA and PMAPOSS-b-P(AA-co-St), were synthesized consecutively by reversible additionfragmentation chain transfer and selective hydrolysis, and characterized by 1H NMR, 13C NMR, Fourier transform infrared spectroscopy and gel permeation chromatography. In the presence of the nearly gradient styrene distribution along the hydrophilic block with a feed molar ratio of tert-butyl acrylate (tBA) to St being 10/1, patterned core-corona nanoparticles (NPs) were formed from the mixture of good/selective solvents (THF/water) by a simple evaporation process at room temperature. With the extending of the co-block length, the self-assembled NPs exhibited phase separation behavior of spheres-dispersed, onion-like and onion-cluster hierarchical structures in turn. However, while a change in the feed molar ratio occurred, it resulted in the formation of typical core-shell micelles (20/1, tBA/St) and disordered particles (5/1, tBA/St), respectively. Furthermore, the self-assembly behavior of PMAPOSS-b-P(AA-co-St) in DMF was investigated, which showed that it could perform a mixture morphology of well-dispersive sphere micelles and large aggregate of micelles. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012