Aqueous Synthesis of Upper Critical Solution Temperature and Lower Critical Solution Temperature Copolymers through Combination of Hydrogen‐Donors and Hydrogen‐Acceptors
作者：Jianlei Lu, Mengdi Xu, Yi Lei, Lihao Gong, Chuanzhuang Zhao
關鍵字：UCST, LCST, aqueous synthesis
論文來源：期刊
具體來源：Macromol. Rapid Commun.
發表時間：2021年
The synthesis of thermo‐responsive polymers from non‐responsive and water‐soluble monomers has great practical advantages but significant challenges. Herein, the authors report a novel aqueous copolymerization strategy to prepare polymers with tunable upper critical solution temperature (UCST) or lower critical solution temperature (LCST) from non‐responsive monomers. Acrylic acid (AAc), N‐vinylpyrrolidone (NVP), and acrylamide (AAm) are copolymerized in water, yielding copolymers with UCST behavior. Interestingly, by simply replacing AAm with its methylated homologue, dimethyl acrylamide (DMA), the thermo‐responsiveness of the copolymers is converted into LCST‐type. The cloud points of the copolymers can be tuned rationally with their monomer ratios and the condition of the solvent. The UCST property of the poly(AAc-NVP-AAm) comes from the AAc–AAm and AAc–NVP hydrogen‐bonds, while the LCST property of poly(AAc-NVP-DMA) originates from the hydrophobic aggregation of AAc-NVP complex and DMA, as indicated by temperature‐dependent 1H NMR and dynamic light scattering.