Poly(lactic acid)/poly(ethylene glycol) stereocomplexed physical hydrogels showing thermally-induced gel–sol–gel multiple phase transitions†,Materials Chemistry Frontiers

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Poly(lactic acid)/poly(ethylene glycol) stereocomplexed physical hydrogels showing thermally-induced gel–sol–gel multiple phase transitions†
Materials Chemistry Frontiers ( IF 6.0 ) Pub Date : 2017-12-12 00:00:00 , DOI: 10.1039/c7qm00502d
Hailiang Mao _{1,

2,

3,

4,

5} , Chen Wang _{5,

6,

7,

8,

9} , Xiaohua Chang _{1,

2,

3,

4,

5} , Heqing Cao _{1,

2,

3,

4,

5} , Guorong Shan _{1,

2,

3,

4,

5} , Yongzhong Bao _{1,

2,

3,

4,

5} , Pengju Pan _{1,

2,

3,

4,

5}

Affiliation

Stereocomplexation of complementary chiral blocks has been a feasible way to prepare thermoresponsive physical gels (or thermogels). Understanding the thermoresponsive phase behavior of stereocomplexable amphiphilic copolymers in water is essential to prepare thermogels with tunable physical properties. Herein, we use an enantiomeric mixture of the poly(D-lactic acid) (PDLA)/poly(ethylene glycol) (PEG) diblock copolymer and the poly(L-lactic acid) (PLLA)/PEG triblock copolymer as a stereocomplexable system and report a novel thermogel that exhibits unique gel–sol–gel multiple transitions upon heating. The thermally-induced phase transition of the PEG–PDLA/PLLA–PEG–PLLA thermogel was governed by the copolymer composition and the stereocomplexation of PLLA/PDLA segments. The molecular motion of PEG segments enhances during the gel–sol transition but slows down in the subsequent sol–gel transition. The gel–sol and sol–gel transitions that occurred at low and high temperatures are driven by the increased mobility of PEG segments and micelles and the promoted PLLA/PDLA stereocomplexation, respectively. PEG–PDLA/PLLA–PEG–PLLA gels can be used to capsulate and release a hydrophobic drug; the drug release rate increases as the content of hydrophilic blocks increases.

中文翻译：

聚乳酸/聚乙二醇立体复合物理水凝胶，显示热诱导的凝胶-溶胶-凝胶多相转变†

互补手性嵌段的立体复合是制备热响应性物理凝胶（或热凝胶）的可行方法。了解可立体络合的两亲共聚物在水中的热响应相行为对于制备具有可调物理性质的热凝胶至关重要。在此，我们使用聚（D-乳酸）（PDLA）/聚（乙二醇）（PEG）二嵌段共聚物和聚（L-乳酸）（PLLA）/ PEG三嵌段共聚物作为立体可络合体系，并且报道了一种新颖的热凝胶，该热凝胶在加热时表现出独特的凝胶-溶胶-凝胶多重转变。PEG–PDLA / PLLA–PEG–PLLA热凝胶的热诱导相变受共聚物组成和PLLA / PDLA链段的立体络合的支配。PEG段的分子运动在凝胶-溶胶转变过程中增强，但在随后的溶胶-凝胶转变过程中变慢。分别在PEG段和胶束中增加的迁移率以及促进的PLLA / PDLA立体复合体驱动了在低温和高温下发生的凝胶-溶胶和溶胶-凝胶转变。PEG-PDLA / PLLA-PEG-PLLA凝胶可用于包封和释放疏水性药物。药物释放速率随亲水性嵌段含量的增加而增加。

更新日期：2017-12-12

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