Hybrid Starlike Block Copolymer POSS–(PDMAEMA-b-PNIPAm)8: Thermal Gelation and Its Blends with Poly(vinyl alcohol),Macromolecules

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Hybrid Starlike Block Copolymer POSS–(PDMAEMA-b-PNIPAm)8: Thermal Gelation and Its Blends with Poly(vinyl alcohol)
Macromolecules ( IF 5.1 ) Pub Date : 2016-06-03 00:00:00 , DOI: 10.1021/acs.macromol.6b00534
Xin Zhou ₁ , Xiaoshan Fan ₁ , Chaobin He _{1,

2}

Affiliation

A novel thermogelling polyhedral oligomeric silsesquioxane–poly(2-(dimethylamino)ethyl methacrylate-b-N-isopropylacrylamide), POSS–(PDMAEMA-b-PNIPAm)₈, star-shaped block copolymer was synthesized by using RAFT polymerization. In aqueous solution this copolymer (≥10 wt %) underwent sol-to-gel transition as the temperature increased. The network structure and rheology properties of POSS–(PDMAEMA-b-PNIPAm)₈ block copolymers could be facilely tuned by blending the poly(vinyl alcohol) into the in situ forming gel system. The presence of PVA could enhance not only the rheological properties but also the thermal sensitivity of the hydrogels. It was observed that the highest storage modulus G′, which is 25 times larger than that of pure star-shaped block copolymer gel, was achieved with 3 wt % content of PVA in the mixture. Moreover, it was found that the addition of PVA could markedly counteract the effect of intramolecular interaction of “arms”. Network structures formed by physically close-packed star-shaped polymer aggregates and PVA interpenetrating within 3D star-shaped polymer network were proposed to be responsible for the dramatic change of rheological behaviors observed in this study, which is also correlated to their corresponding morphologies investigated by using ATR-FTIR, SAXS, and DLS.

中文翻译：

星形杂化嵌段共聚物POSS–（PDMAEMA- b -PNIPAm）₈：热凝胶化及其与聚乙烯醇的共混物

一种新型的热凝胶多面体低聚倍半硅氧烷-聚甲基丙烯酸2-（二甲氨基）乙酯-b - N-异丙基丙烯酰胺，POSS-（PDMAEMA- b- PNIPAm）₈，是利用RAFT聚合合成的星形嵌段共聚物。在水溶液中，随着温度升高，该共聚物（≥10wt％）经历了溶胶-凝胶转变。POSS–（PDMAEMA- b -PNIPAm）₈嵌段共聚物的网络结构和流变性质可以通过将聚乙烯醇共混到原位来轻松调节形成凝胶系统。PVA的存在不仅可以增强流变性，而且可以提高水凝胶的热敏性。观察到，在混合物中PVA的含量为3wt％时，获得了最高的储能模量G '，其为纯星形嵌段共聚物凝胶的最高储能模量G '的25倍。此外，发现添加PVA可以显着抵消“臂”的分子内相互作用的影响。提出由物理上紧密堆积的星形聚合物聚集体和3D星形聚合物网络内的PVA互穿形成的网络结构，是造成本研究中观察到的流变行为急剧变化的原因，这也与它们研究的相应形态有关使用ATR-FTIR，SAXS和DLS。

更新日期：2016-06-03

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