Amphiphilic diblock copolymers bearing pendant aromatic acetal groups: Synthesis and tunable pH-triggered assembly/disassembly transition behavior.

ABSTRACT A novel aromatic acetal-based acid-labile monomer 2-phenyl-5-ethyl-5-acryloxymethyl-1,3-dioxacyclohexane (HEDPA) was synthesized and polymerized by reversible addition fragmentation chain transfer (RAFT) polymerization using alkynyl functional chain transfer agent (CTA-Alk). Afterward, a series of amphiphilic diblock copolymers composed of fixed hydrophobic poly(2-phenyl-5-ethyl-5-acryloxymethyl-1,3-dioxacyclohexane) (PDAEP) segments and various lengths of hydrophilic mPEG segments were prepared through click reaction between alkynyl-terminated PDAEP and azido-terminated mPEG. The self-assembly behaviors of the diblock copolymers were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), fluorescence spectroscopy, and 1H NMR. These results indicated that the diblock copolymers could self-assemble into nano-sized micelles with PDAEP cores and PEG coronas in aqueous solution. DLS, fluorescence spectroscopy and UV-vis spectroscopy were used to monitor the pH-triggered assembly/disassembly transition of the micelles. These results showed that the assembly/disassembly transition behaviors of the diblock copolymers micelles can be adjusted by changing the lengths of the mPEG segments. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1537-1547 [ABSTRACT FROM AUTHOR]