Semi-bald Micelles and Corresponding Percolated Micelle Networks of Thermogels
Semi-bald Micelles and Corresponding Percolated Micelle Networks of Thermogels
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热凝胶的半秃胶束和相应的渗透胶束网络
DOI：
10.1021/acs.macromol.8b01014
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发表时间：
2018-08-28
期刊：
影响因子：
5.5
通讯作者：
Ding, Jiandong
中科院分区：
文献类型：
--
作者：
Cui, Shuquan;Yu, Lin;Ding, Jiandong
两亲性聚酯和聚醚嵌段共聚物水热凝胶作为一种可注射、可生物降解的水凝胶，在生物医学领域显示出巨大的应用潜力。这是具有挑战性的，以揭示背后的机制与溶胶-凝胶转变加热时的逆热凝胶。在此，计算机模拟和相应的实验相结合，以检查的两亲性两嵌段共聚物的甲氧基聚（乙二醇）和聚（D，L-丙交酯-共-乙交酯）的水系统。采用开环聚合法合成了该共聚物，并利用三维动态光散射和漫反射光谱对其水溶液的热凝胶行为进行了表征。并采用荧光共振能量转移、碳13核磁共振等方法探讨了热凝胶过程中的结构变化。对相应的多链系统进行了动态Monte Carlo模拟。首次提出了一种新型的胶束--半秃胶束作为热凝胶化的前驱体，并从模拟和实验中得到了证实。我们证明，热凝胶结构是一个疏水通道，从半秃胶束演变成的疏水胶束网络。在链水平上讨论了热凝胶化机理。在机理研究的基础上，提出了热凝胶的分子设计原则。
As an injectable and biodegradable hydrogel, thermogels of amphiphilic block copolymers of polyester and polyether in water show great potential in biomedical fields. It is challenging to reveal the mechanism behind the reversed thermogelling with sol-gel transition upon heating. Herein, a computer simulation and corresponding experiments are combined to examine aqueous systems of amphiphilic diblock copolymer of methoxypoly(ethylene glycol) and poly(D,L-lactide-co-glycolide). We synthesized the copolymer via ring-opening polymerization and characterized the thermogelling behavior of its aqueous solution by 3D dynamic light scattering and diffusing wave spectroscopy. Fluorescence resonance energy transfer and C-13 NMR spectroscopy etc. were also adopted to explore the structure change during thermogelation. A dynamic Monte Carlo simulation was performed for a corresponding multichain system. A new type of micelle, the semi-bald micelle, was first proposed as the precursor for thermogelling and was confirmed from both simulations and experiments. We demonstrate that the thermogel structure is a percolated micelle network with hydrophobic channels that evolved from the semi-bald micelles. The thermogelling mechanism is discussed at the chain level. On the basis of the mechanism study, we put forward the molecular design principle of the thermogels.