Amphiphilic diblock copolymers bearing pendant aromatic acetal groups: Synthesis and tunable pH‐triggered assembly/disassembly transition behavior. Issue 11 (17th December 2015)

• Record Type: Journal Article
• Authors: Zhang, Wanbin; Fan, Xiaodong; Zhang, Haitao; Zhu, Xiuzhong; Tian, Wei
• Is Part Of: Journal of polymer science. Volume 54:Issue 11(2016)
• Page Start: 1537
• Page End: 1547
• Publication Date: 2015-12-17
• Subjects: amphiphilic block copolymer -- acetal -- RAFT polymerization -- self‐assembly -- synthesis; 547
• DOI: 10.1002/pola.28008
• Languages: English
• ISSNs: 0887-624X

Abstract

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 1 H 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 : Amphiphilic diblock copolymers (PDAEP‐ b ‐PEG) bearing pendant acid‐labile acetal groups were synthesized by combining RAFT polymerization with click reaction. The diblock copolymers can self‐assemble into spherical micelles in aqueous solution. The micelles are stable in a neutral environment, however, in an acidic environment, acetal groups hydrolyzed gradually, and led to the swelling of the micelles. When the acetals hydrolysis was carried out for a sufficiently long time, the micelles disassembled and were converted to water soluble unimers.