Double-network hydrogels have attracted much attention because of their superior mechanical properties, which are more similar to rubbers and soft tissues than classic hydrogels. In this report, plasmonic gold nanorods (AuNRs) were incorporated into a stretchable double-network hydrogel, composed of alginate and acrylamide. The impact of gold nanorod concentration and surface chemistry on bulk mechanical properties such as Young's modulus and elongation at break was investigated. AuNRs with three different surface chemistries, cetyltrimethylammonium bromide, thiolated poly(ethylene glycol), and 11-mercaptoundecanoic acid were successfully dispersed into alginate/polyacrylamide hydrogels. The AuNR-loaded hydrogels could be reversibly stretched, leading to AuNR reversible alignment along the stretch direction as judged by polarized optical spectroscopy. With the proper surface chemistry, hydrogel nanorod composites were able to be stretched to more than 3000% their initial length without fracturing. These results show that plasmonic gold nanorods can be well dispersed in multi-component polymer systems, certain surface chemistries can enhance the bulk mechanical properties, and AuNR orientation can be controlled through varying strains on the matrix.

中文翻译：

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金纳米棒对可拉伸水凝胶的机械性能产生影响。

双网状水凝胶由于其卓越的机械性能而备受关注，与传统的水凝胶相比，其与橡胶和软组织的相似性更高。在本报告中，将等离激元金纳米棒（AuNRs）掺入了由藻酸盐和丙烯酰胺组成的可拉伸双网络水凝胶中。研究了金纳米棒浓度和表面化学性质对整体机械性能（如杨氏模量和断裂伸长率）的影响。具有三种不同表面化学性质的AuNRs，十六烷基三甲基溴化铵，硫醇化聚乙二醇和11-巯基十一烷酸已成功分散到藻酸盐/聚丙烯酰胺水凝胶中。载有AuNR的水凝胶可以可逆地拉伸，导致偏振方向上的AuNR沿拉伸方向可逆排列。通过适当的表面化学作用，水凝胶纳米棒复合材料能够被拉伸至其初始长度的3000％以上而不会破裂。这些结果表明，等离激元金纳米棒可以很好地分散在多组分聚合物体系中，某些表面化学性质可以增强整体机械性能，并且AuNR取向可以通过改变基质上的应变来控制。