Load-Bearing Nanostructures in Composites of Chitosan with Anionic Surfactants: Implications for Programmable Mechanomaterials
Load-Bearing Nanostructures in Composites of Chitosan with Anionic Surfactants: Implications for Programmable Mechanomaterials
复制标题
DOI：
10.1021/acsanm.2c00560
复制
发表时间：
2022-05
影响因子：
5.9
通讯作者：
Suhas Gotla;Christopher Tong;S. Matysiak
中科院分区：
文献类型：
--
作者：
Suhas Gotla;Christopher Tong;S. Matysiak
多糖如壳聚糖（CHT）可以在许多材料应用中可持续地取代合成聚合物，但它们的天然机械性能往往低于标准。添加离子型表面活性剂如阴离子十二烷基硫酸钠（SDS）可以在多糖材料（包括CHT）中带来显著的机械增强。在碱性pH下，CHT是中性的并形成弹性水凝胶，但CHT在酸性pH下的阳离子性质使得能够与SDS离子交联，导致具有上级强度的粘弹性水凝胶。因此，SDS：CHT已成为一个有前途的平台，空间和动态规划的水凝胶具有独特的响应机械负荷，但其承载机制的纳米级起源仍然难以捉摸。为了解决这一差距，CHT水凝胶网络在不同的pH值和SDS浓度下自组装，并使用多尺度建模管道进行机械测试。除了产生与实验报告一致的机械性能的自组装，我们的方法揭示了不同的pH值和SDS依赖的承重机制。我们发现，基本的CHT网络进行负载依赖性结晶，类似于拉伸橡胶，而SDS胶束肩负的负载响应在酸性SDS：CHT网络合并成更大的胶束。这些发现可能使这些编程机制适应其他多糖-表面活性剂组合，导致现有SDS：CHT应用的机械稳健性的改善，并激发新应用的开发。
Polysaccharides like chitosan (CHT) can sustainably replace synthetic polymers in many material applications, but their native mechanical properties are often subpar. Addition of ionic surfactants like the anionic sodium dodecylsulfate (SDS) can bring about dramatic mechanical enhancements in polysaccharide materials, including those of CHT. At basic pH, CHT is neutral and forms elastic hydrogels, but the cationic nature of CHT at acidic pH enables ionic cross-linking with SDS, leading to viscoelastic hydrogels with superior strength. Thus, SDS:CHT has emerged as a promising platform for spatial and dynamic programming of hydrogels with unique responses to mechanical loads, but the nanoscale origins of their load-bearing mechanisms remain elusive. To address this gap, CHT hydrogel networks were self-assembled at varying pH values and SDS concentrations and mechanically tested using a multiscale modeling pipeline. In addition to yielding self-assemblies with mechanical properties consistent with experimental reports, our methods revealed distinct pH- and SDS-dependent load-bearing mechanisms. We found that basic CHT networks underwent load-dependent crystallization, similar to stretched rubber, while SDS micelles shouldered the load response in acidic SDS:CHT networks by merging into larger micelles. These findings may enable the adaptation of these programming mechanisms for other polysaccharide–surfactant combinations, lead to the improvement of mechanical robustness of existing SDS:CHT applications, and inspire the development of new applications.