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

摘要

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 addition-fragmentation chain transfer and selective hydrolysis, and characterized by ~1H NMR, ~(13)C 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.