Wang Feng, Yong Xueyong, Deng Jianping, Wu Youping
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology Beijing 100029 China
A State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology Beijing 100029 China.
RSC Adv. 2018 May 8;8(30):16773-16780. doi: 10.1039/c8ra01167b. eCollection 2018 May 3.
As a type of important intelligent materials, shape memory hydrogels (SMHs) have gathered a lot of interest due to their promising applications. However, preparing SMHs with excellent mechanical properties still remains a big challenge. In this study, a new type of SMHs with excellent mechanical strength is created. The SMHs were prepared by free radical micellar polymerization of hydrophobic monomer (octadecyl acrylate) with gelatin as emulsifier in a aqueous system containing hydrophilic monomer (,-dimethylacrylamide, DMA) and clay as reinforcing filler. The polymerization provided physically cross-linked network structures constructed by two non-covalent interactions, hydrophobic association formed by monomer units and multiple H-bonds among inorganic clay, gelatin and DMA. A judicious combination of the two physically cross-linked networks significantly improved the mechanical strength of hydrogels. More interestingly, the hydrogels demonstrated shape memory behavior due to the hydrophobic poly(octadecyl acrylate) domains. The novel SMHs are expected to find practical applications as biomaterials.
作为一类重要的智能材料，形状记忆水凝胶（SMHs）因其广阔的应用前景而备受关注。然而，制备具有优异力学性能的SMHs仍然是一个巨大的挑战。在本研究中，制备出了一种具有优异机械强度的新型SMHs。该SMHs是通过在含有亲水单体（N,N-二甲基丙烯酰胺，DMA）和作为增强填料的粘土的水体系中，以明胶为乳化剂，使疏水单体（丙烯酸十八酯）进行自由基胶束聚合而制备的。该聚合反应提供了由两种非共价相互作用构建的物理交联网络结构，即单体单元形成的疏水缔合以及无机粘土、明胶和DMA之间的多个氢键。这两种物理交联网络的合理组合显著提高了水凝胶的机械强度。更有趣的是，由于疏水的聚（丙烯酸十八酯）域，水凝胶表现出形状记忆行为。这种新型SMHs有望作为生物材料找到实际应用。
