Key Laboratory for Special Functional Materials of Ministry of Education, School of Materials and Engineering, Henan University, Kaifeng 475000, China.
Nanoscale. 2023 May 25;15(20):9060-9068. doi: 10.1039/d3nr01362f.
The brick-and-mortar architecture of nacre shells brings radiant structural colors, high toughness, and strength, inspiring numerous designs for structural and optical materials. However, constructing structural color is not always easy, especially among soft materials where aligning components against random and dynamically active environments is generally difficult. Here, we propose a composite organohydrogel capable of visualizing multiple levels of stress, featuring broad tunable mechanical properties, dynamic mechanochromism, deep low working temperatures, and anti-drying attributes. In the composite gels, the intercalation between α-zirconium phosphate (α-ZrP) nanoplates and poly-(diacetone acrylamide--acrylamide) is induced by shear-orientation-assisted self-assembly followed by solvent replacement. The highly tailorable (from ∼780 nm to ∼445 nm) range of colors was achieved by regulating the concentration of α-ZrP and glycerol inside the matrix. With the help from glycerol, the composite gels exhibited long-term stability (7 d) in the arid condition and remarkable low-temperature tolerance (-80 °C). The extraordinary mechanical property (compressive strength up to 119 MPa) of composite gels is achieved by the assembled α-ZrP plates with a small aspect ratio, high negative charge repulsion, and abundant hydrogen bonding sites. As a result, the mechanochromic sensor based on the composite gel enjoys a wide range of stress detection (0-1862 KPa). This study provides a new strategy for constructing high strength structural-colored gels, opening up opportunities for sensitive yet strong mechanochromic sensors in extreme environments.
珍珠母层状结构赋予贝壳绚丽的结构色、高韧性和强度，为结构和光学材料的设计提供了诸多灵感。然而，构建结构色并不总是那么容易，尤其是在软材料中，通常很难使组件在随机且动态活跃的环境中保持对齐。在这里，我们提出了一种复合有机水凝胶，它可以可视化多个级别的应力，具有广泛可调的机械性能、动态力致变色、深低温工作和抗干燥属性。在复合凝胶中，α-磷酸锆（α-ZrP）纳米片和聚（二丙酮丙烯酰胺-丙烯酰胺）之间的插层是通过剪切定向辅助自组装后进行溶剂置换诱导的。通过调节基质内α-ZrP 和甘油的浓度，可以实现高度可调节的（从 ∼780 nm 到 ∼445 nm）颜色范围。在甘油的帮助下，复合凝胶在干燥条件下具有长达 7 天的长期稳定性（-80 °C）和显著的耐低温性。复合凝胶具有出色的机械性能（压缩强度高达 119 MPa），这是通过组装的具有小纵横比、高负电荷排斥和丰富氢键结合位点的α-ZrP 板实现的。结果，基于复合凝胶的力致变色传感器具有广泛的应力检测范围（0-1862 KPa）。这项研究为构建高强度结构色凝胶提供了新策略，为极端环境下敏感且坚固的力致变色传感器开辟了机会。
