State Key Laboratory of Pulp and Paper Engineering , South China University of Technology , Guangzhou 510640 , China.
Guangdong Engineering Research Center for Green Fine Chemicals, Guangzhou 510640 , China.
Biomacromolecules. 2019 May 13;20(5):2096-2104. doi: 10.1021/acs.biomac.9b00322. Epub 2019 Apr 24.
Stretchable and compressible hydrogels based on natural polymers have received immense considerations for electronics. The feasibility of using pure natural polymer-based hydrogels could be improved if their mechanical behaviors satisfy the requirements of practical applications. Herein, we report highly stretchable (tensile strain ∼126%) and compressible (compression strain ∼80%) cellulose ionic hydrogels (CIHs) among pure natural polymer-based hydrogels including cellulose, chitin, and chitosan via chemical cross-linking based on free radical polymerization of allyl cellulose in NaOH/urea aqueous solution. In addition, the hydrogels have good transparency (transmittance of ∼89% at 550 nm) and ionic conductivity (∼0.16 mS cm) and can be worked at -20 °C without freezing and visual loss of transparency. Moreover, the CIHs can serve as reliable and stable strain sensors and have been successfully used to monitor human activities. Significantly, the various properties of hydrogel can be controlled through rationally adjusting the chemically cross-linked density. Our methodology will prove useful in developing the satisfied mechanical and transparent CIHs for a myriad of applications in flexible electronics.
基于天然聚合物的可拉伸和可压缩水凝胶在电子学领域受到了广泛关注。如果其机械性能满足实际应用的要求，那么使用纯天然聚合物基水凝胶的可行性将会提高。在此，我们通过在 NaOH/尿素水溶液中基于丙烯基纤维素的自由基聚合反应进行化学交联，在包括纤维素、甲壳素和壳聚糖在内的纯天然聚合物基水凝胶中报告了具有高拉伸性（拉伸应变约为 126%）和可压缩性（压缩应变约为 80%）的纤维素离子水凝胶（CIH）。此外，水凝胶具有良好的透明度（在 550nm 处的透光率约为 89%）和离子电导率（约 0.16mScm），并且可以在-20°C 下工作而不会冻结且透明度不会明显降低。此外，CIH 可用作可靠且稳定的应变传感器，并已成功用于监测人体活动。重要的是，通过合理调整化学交联密度，可以控制水凝胶的各种性质。我们的方法将有助于开发满足要求的机械性能和透明 CIH，以满足在柔性电子产品中应用的需求。
