Stereocomplexed and homocrystalline thermo-responsive physical hydrogels with a tunable network structure and thermo-responsiveness

编号 020026205

推送时间 20201026

研究领域 林产化工 

年份 2020 

类型 期刊 

语种 英语

标题 Stereocomplexed and homocrystalline thermo-responsive physical hydrogels with a tunable network structure and thermo-responsiveness

来源期刊 Journal of Materials Chemistry B

期 第262期

发表时间 20200721

关键词 NANOCOMPOSITE HYDROGELS;  POLY(LACTIC ACID);  POLY(N-ISOPROPYLACRYLAMIDE);  TOUGH;  GELS;  ELASTOMERS;  BEHAVIOR;  MEMORY;  CHAIN; 

摘要 The widespread application of thermo-responsive hydrogels requires materials with robust mechanical properties and tunable responsiveness. Herein, we report robust thermo-responsive physical hydrogels with a tunable network structure and responsiveness by controlling the manner of crystallization of hydrophobic blocks. Biocompatible, stereocomplexable poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) were introduced into thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) to obtain the enantiomeric grafted copolymers PNIPAM-g-PLLA and PNIPAM-g-PDLA and their corresponding hydrogels. The hydrophobic PLLA/PDLA domains served as physical crosslinking junctions in the hydrogels. The crystalline structure of the hydrogels can be facilely tuned by varying the ratio of PLLA/PDLA enantiomeric blocks. Stereocomplex (SC) crystallization between PLLA and PDLA facilitates the formation of H-bonded hydrophobic domains with denser chain packing, which endows the racemic hydrogels with a stronger network structure, higher mechanical strength, and better solvent resistance compared to enantiopure examples. The hydrogels exhibit good thermo-sensitivity in water; the stronger racemic hydrogel network restricts volume shrinkage and water desorption at high temperatures, enabling the facile control of thermo-responsiveness. The crystallization-tuned thermo-responsiveness of racemic and enantiopure hydrogels also allows for the design of assembled bilayer hydrogels capable of thermally triggered reversible shape morphing.

服务人员 尚玮姣

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