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Phototunable Cloud Point Temperatures Stemming from Cyclic Topology: Synthesis and Thermal Phase Transition Behavior of Cyclic Poly( N ‐acryloylsarcosine methyl ester)
Author(s) -
Wu Zhigang,
Zhang Hualong,
Liu Chao,
Hong Chunyan
Publication year - 2021
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.202100136
Subject(s) - chain transfer , cloud point , glass transition , phase transition , polymerization , monomer , materials science , polymer chemistry , polymer , topology (electrical circuits) , chemistry , thermodynamics , radical polymerization , organic chemistry , physics , mathematics , combinatorics , composite material , extraction (chemistry)
Cyclic polymers possess distinct properties compared with their linear counterparts, such as smaller hydrodynamic volume, lower viscosity, and higher glass‐transition temperature, etc. To explore the impact of the cyclic topology on the thermo‐induced phase transition behavior of poly( N ‐acryloylsarcosine methyl ester) (PNASME), the anthracene‐terminated telechelic PNASMEs are synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization of monomer NASME using a bifunctional chain transfer agent (CTA) with two anthryl groups. Subsequently, cyclic PNASMEs are prepared via UV‐induced cyclization under 365 nm UV. There are considerable increases (up to 50 °C) for the cloud point temperatures ( T cp s) of cyclic PNASMEs compared with the linear counterparts. In view of the increment, the T cp of PNASME is tuned by varying the cyclic/linear ratio (the molar ratio between cyclic PNASME and linear PNASME in the product) with different irradiation time.