Department of Chemical Engineering, Texas Tech University , Lubbock, Texas 79409, United States.
ACS Appl Mater Interfaces. 2013 Sep 11;5(17):8633-40. doi: 10.1021/am402185r. Epub 2013 Aug 20.
Enhancement of toughness in nanomaterial-based hydrogels is a critical metric for many of their engineering applications. Pristine graphene-polyacrylamide (PAM) hydrogels are synthesized via in situ polymerization of acrylamide monomer in PAM-stabilized graphene dispersion. In-situ polymerization leads to the uniform dispersion of the graphene sheets in the hydrogel. The graphene sheets interact with the elastic chains of the hydrogel through physisorption and permit gelation in the absence of any chemical cross-linker. This study represents the first report of pristine graphene as a physical cross-linker in a hydrogel. The properties of the graphene-polymer hydrogel are characterized by rheological measurements and compressive tests, revealing an increase in the storage modulus and toughness of the hydrogels compared to the chemically cross-linked PAM analogues. The physically cross-linked graphene hydrogels also exhibit self-healing properties. These hydrogels prove to be efficient precursors for graphene-PAM aerogels with enhanced electrical conductivity and thermal stability.
增强纳米材料基水凝胶的韧性是其许多工程应用的关键指标。通过丙烯酰胺单体在 PAM 稳定的石墨烯分散体中的原位聚合合成了原始石墨烯-聚丙烯酰胺（PAM）水凝胶。原位聚合导致石墨烯片在水凝胶中均匀分散。石墨烯片通过物理吸附与水凝胶的弹性链相互作用，并允许在没有任何化学交联剂的情况下凝胶化。这项研究首次报道了原始石墨烯作为水凝胶中的物理交联剂。通过流变学测量和压缩试验对石墨烯-聚合物水凝胶的性能进行了表征，结果表明与化学交联的 PAM 类似物相比，水凝胶的储能模量和韧性均有所提高。物理交联的石墨烯水凝胶还表现出自修复性能。这些水凝胶被证明是具有增强导电性和热稳定性的石墨烯-PAM 气凝胶的有效前体。
