二茂铁络合作用极大的提高了多刺激响应性水凝胶的溶胀度
J. Am. Chem. Soc. 2016, 138, 6643−6649
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水凝胶作为一种亲水性的三维聚合物网络，因其突出的特点及用途广泛一直是科学界的研究热点。溶胀-收缩转变的特点使水凝胶可应用于制动器及药物运输。主体−客体相互作用在制备具有多功能的超分子聚合物及自修复材料中起着重要的作用。然而，很少有人通过主体−客体相互作用在宏观尺度控制的水凝胶的溶胀收缩性能。前人研究的水凝胶膨胀收缩转换程度小及响应外部刺激效率低。因此，通过主体−客体相互作用实现多刺激响应性水凝胶在宏观尺度上膨胀−收缩转换仍然是一个很大的挑战。 南京大学的王乐勇教授团队制备了一种侧链含有二茂铁基团的聚合物智能水凝胶。将其浸入到WP6水溶液中，智能水凝胶溶胀率由于WP6和二茂铁的主体客体相互作用大幅度提高，重量是浸入到纯水中的11倍。此外，通过调节WP6-二茂铁包合物的分离/形成或电荷强度来实现水凝胶对外部刺激的响应性，包括温度、PH、氧化还原性等。通过调节PH解离WP6-二茂铁包合物从而实现水凝胶在药物控释方面的应用。这是首次报导通过WP6-二茂铁盐的主客相互作用实现智能水凝胶优异的溶胀-收缩行为。 The swelling−shrinking transition of hydrogels is crucial for their wide applications such as actuators and drug delivery. Leyong Wang who working in the School of Nanjing University fabricated a smart hydrogel with ferrocene groups on pendant of polymer networks. While it was immersed in the water-soluble pillar[6]arene (WP6) aqueous solution, the hydrogel was dramatically swollen, which was an approximately 11-fold promotion in weight compared with that in pure water, due to the formation of the inclusion complexes between WP6 and ferrocene groups in the hydrogel. In particular, the well-swollen hydrogel exhibited good responsiveness to multistimuli including temperature, pH, redox, and competitive guests by tuning the dissociation/formation of WP6−ferrocene inclusion complexes or the strength of their charges. Meanwhile, potential application of such a smart hydrogel in pH-responsive drug release was demonstrated as well. （闫欢欢） |