Self-healable, super tough graphene oxide-poly(acrylic acid) nanocomposite hydrogels facilitated by dual cross-linking effects through dynamic ionic interactions
Self-healable, super tough graphene oxide-poly(acrylic acid) nanocomposite hydrogels facilitated by dual cross-linking effects through dynamic ionic interactions
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DOI：
10.1039/c5tb00075k
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发表时间：
2015-01-01
影响因子：
7
通讯作者：
Xie, Xu-Ming
中科院分区：
文献类型：
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作者：
Zhong, Ming;Liu, Yi-Tao;Xie, Xu-Ming
在这里，我们提出了一种简单的，一锅原位自由基聚合策略，以Fe3+离子作为交联剂制备自愈的，超韧性的氧化石墨烯(GO)-聚丙烯酸（PAA）纳米复合水凝胶。GO-PAA纳米复合水凝胶的三维网络结构是通过动态离子相互作用的双重交联效应促进的：(i)第一个交联点是Fe3+离子，在PAA链之间产生离子交联；（ii）第二个交联点是氧化石墨烯纳米片通过Fe3+配位连接PAA链。当氧化石墨烯-PAA纳米复合水凝胶处于拉伸状态时，PAA链之间的离子相互作用可以动态断裂和重组以耗散能量，而与PAA链配合的氧化石墨烯纳米片保持水凝胶的构型，并作为应力传递中心将应力传递给聚合物基体。在这方面，GO-PAA纳米复合水凝胶具有优异的韧性（抗拉强度为777 kPa，延伸功为11.9 MJ m(-3)）和拉伸性（断裂伸长率为2980%）。此外，在45℃下处理48 h后，切断的GO-PAA纳米复合水凝胶表现出良好的自愈性能（抗拉强度为495 kPa，断裂伸长率为2470%）。具有自愈性、超韧性的GO-PAA纳米复合水凝胶为开发先进的软材料奠定了基础，在现代生物医学工程和技术中具有潜在的应用前景。
Here we propose a facile, one-pot in situ free radical polymerization strategy to prepare self-healable, super tough graphene oxide (GO)-poly(acrylic acid) (PAA) nanocomposite hydrogels by using Fe3+ ions as a cross-linker. The 3-dimensional network structure of the GO-PAA nanocomposite hydrogels is facilitated by dual cross-linking effects through dynamic ionic interactions: (i) the first cross-linking points are Fe3+ ions creating ionic cross-linking among PAA chains; (ii) the second cross-linking points are GO nanosheets linking PAA chains through Fe3+ coordination. When the GO-PAA nanocomposite hydrogels are under stretching conditions, the ionic interactions among PAA chains can dynamically break and recombine to dissipate energy, while the GO nanosheets coordinated to the PAA chains maintain the configuration of the hydrogels and work as stress transfer centers transferring the stress to the polymer matrix. In this regard, the GO-PAA nanocomposite hydrogels exhibit superior toughness (tensile strength = 777 kPa, work of extension = 11.9 MJ m(-3)) and stretchability (elongation at break = 2980%). Furthermore, after being treated at 45 degrees C for 48 h, the cut-off GO-PAA nanocomposite hydrogels exhibit good self-healing properties (tensile strength = 495 kPa, elongation at break = 2470%). The self-healable, super tough GO-PAA nanocomposite hydrogels lay a basis for developing advanced soft materials holding potential applications in modern biomedical engineering and technology.