title: Synthesis, Thermal Properties, and Thermoresponsive Behaviors of Cyclic Poly(2-(dimethylamino)ethyl Methacrylate)s.
abstract: This study aims at physicochemical properties of thermo- and pH/CO2 -responsive cyclic homopolymers. Three examples of cyclic poly(2-(dimethylamino)ethyl methacrylate)s (PDMAs) are synthesized by combining the reversible addition-fragmentation chain transfer process and the Diels-Alder ring-closure reaction. After cyclization, the glass transition temperature significantly increases (ΔTg = 51.8-59.7 °C) due to the different configurational entropy and end groups, and the maximum decomposition temperature to lose the pendent groups is drastically decreased from 309 to 278 °C. Effects of polymerization degree, polymer concentration, additive of NaCl, and pH/CO2 on lower critical solution temperature behaviors of PDMA aqueous solutions are investigated. The cloud points (Tc ) of ring PDMAs are usually higher than their linear precursors, and the ΔTc values obtained under a fixed condition can reach up to 20.7 °C, revealing the crucial role of the topology effect. This study paves the way for unique properties and applications of smart cyclic polymers and their derivatives.
authors.affiliation: Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: An
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, The Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Qingquan
authors.initials: Q
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, The Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, The Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Youliang
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D003500:Cyclization; D008689:Methacrylates / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009757:Nylons / Q000138:chemical synthesis* / Q000737:chemistry; D013696:Temperature
chemical_list: D008689:Methacrylates; D009757:Nylons; C407037:poly(2-(dimethylamino)ethyl methacrylate)
keywords: Diels-Alder reactions; cyclic polymers; phase transitions; smart polymers; thermal properties