Department of Applied Molecular Chemistry, College of Industrial Technology , Nihon University , 1-2-1 Izumi-cho , Narashino , Chiba 275-8575 , Japan.
Langmuir. 2018 Jul 24;34(29):8480-8488. doi: 10.1021/acs.langmuir.8b01448. Epub 2018 Jul 11.
We investigated the adhesion behavior of nanocomposite hydrogels (NC gels), consisting of unique organic (polymer)-inorganic (clay) network structures, toward inorganic and organic materials. The NC gels exhibit instant and strong adhesion to inorganic and organic substrates with hydrophilic porous surfaces. The NC gels instantly adhere to hydrophilic porous substrates (e.g., unglazed ceramic surfaces and polymer membranes) through simple light contact. In addition, a small piece of NC gel effectively joined two substrate samples (e.g., concrete blocks and bricks) through lamination of the interposing NC gel. The resulting conjoined materials were unable to be separated at the gel-substrate interface; rather, the gel itself fractured upon separation, which indicates that the adhesive strength at the interface is greater than the tensile strength of the NC gel. With the exception of NC gels with very high clay concentrations ( C's), instant strong adhesion and cohesive failure by subsequent stretching were observed for almost all NC gels composed of different polymers or different C values. A thermoresponsive NC gel was reversibly adhered and could be peeled from the surface by stretching (adhesive failure) at a temperature above its transition temperature. The mechanism of instant strong adhesion or reversible adhesion is discussed based on dangling chains that exist on the surfaces of the NC gels composed of polymer-clay networks. The cut surface of an NC gel generally exhibited a higher adhesive strength than the as-prepared surface because of longer dangling chains.
我们研究了纳米复合水凝胶（NC 水凝胶）的黏附行为，它由独特的有机（聚合物）-无机（粘土）网络结构组成，对无机和有机材料具有黏附性。NC 水凝胶对具有亲水多孔表面的无机和有机基底表现出即时且强大的黏附性。NC 水凝胶通过简单的光接触即可立即黏附在亲水多孔基底（如无釉陶瓷表面和聚合物膜）上。此外，一小片 NC 水凝胶通过夹层 NC 水凝胶的层压有效地将两个基底样品（如混凝土块和砖块）连接起来。连接后的材料无法在凝胶-基底界面分离；相反，凝胶本身在分离时断裂，这表明界面处的黏附强度大于 NC 凝胶的拉伸强度。除了粘土浓度非常高（C）的 NC 凝胶外，几乎所有由不同聚合物或不同 C 值组成的 NC 凝胶都表现出即时的强黏附性和随后拉伸时的内聚失效。一种温敏性 NC 水凝胶在其转变温度以上可以通过拉伸（黏附失效）可逆地黏附和从表面剥离。根据由聚合物-粘土网络组成的 NC 凝胶表面存在的悬垂链，讨论了即时强黏附或可逆黏附的机制。由于存在更长的悬垂链，NC 水凝胶的切割表面通常比原始表面具有更高的黏附强度。
