Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, 24044 Dalmine, BG, Italy.
Institute for the Study of Nanostructured Materials, ISMN - CNR, via Salaria Km 29.3, 00015 Monterotondo stazione, Rome, Italy.
J Colloid Interface Sci. 2022 Jul;617:463-477. doi: 10.1016/j.jcis.2022.03.006. Epub 2022 Mar 7.
The broad detection properties of alizarin, not only concerning pH variations but also temperature, glucose and health-like relevant cations alterations, make it a molecule of great scientific interest, particularly for developing multifunctional wearable sensors.
Herein, the alizarin red S dyestuff is bonded with trimethoxy-[3-(oxiran-2-ylmethoxy)propyl]silane, as a sol-gel precursor, to functionalize cotton fabrics. The chemical and structural properties of both plain and silane-functionalized dyestuffs are investigated in solution and solid-state by several chemical-physical characterization techniques.
The hybrid dyestuff characterization reveals the epoxy ring-opening of the silica precursor, leading to covalent linkages to the sulfonic group of alizarin, which retains its structure during the sol-gel reaction. The silane-functionalized halochromic dyestuff shows similar halochromic behaviour as its pristine solution in the investigated pH range, thus demonstrating a color shift from yellow to red due to the protonation/deprotonation reversible mechanism of the chromophore. The reversibility and repeatability of pH-sensing properties of treated cotton fabrics are confirmed by diffuse reflectance and CIELAB color space characterizations. Cotton fabric functionalized with alizarin-containing sol-gel coating shows excellent durability of halochromic properties, thus emerging as a versatile platform for stimuli-responsive materials.
茜素不仅对 pH 值变化，而且对温度、葡萄糖和类似健康的相关阳离子的变化具有广泛的检测特性，这使其成为一个具有巨大科学兴趣的分子，特别是对于开发多功能可穿戴传感器。
本文将茜素红 S 染料与三甲氧基-[3-（环氧乙烷-2-基甲氧基）丙基]硅烷结合，作为溶胶-凝胶前体，对棉织物进行功能化。通过多种物理化学特性分析技术，在溶液和固态中对普通和硅烷功能化染料的化学和结构特性进行了研究。
杂化染料的表征揭示了硅烷前驱体的环氧开环，导致与茜素的磺酸基发生共价键合，在溶胶-凝胶反应过程中保留了其结构。这种硅烷功能化的变色染料在研究的 pH 范围内表现出与原始溶液相似的变色行为，因此由于生色团的质子化/去质子化可逆机制，颜色从黄色变为红色。通过漫反射和 CIELAB 颜色空间特性分析，证实了经处理的棉织物的 pH 传感性能的可逆性和可重复性。用含有茜素的溶胶-凝胶涂层处理的棉织物具有出色的变色性能耐久性，因此成为一种多功能的刺激响应材料平台。
