Abstract:

In this work, composite color-changing hydrogels (SPS) with dual-stimulation response to temperature and pH were successfully prepared by free radical polymerization using sodium dodecylbenzene sulfonate (SDBS) and N-isopropylacrylamide (NIPAm) as the raw materials. The SPS hydrogel had higher temperature sensitivity, and the visible light transmittance of the composite hydrogel showed a linear change with the ambient temperature when the temperature-variable interval was 10—40℃, and the solar modulation rate ΔT_solwas higher than 85.78% before and after discoloration. The composite hydrogel also functioned as a pH discoloration response due to the greatly reduced solubility of SDBS in acidic environments (pH≤2). In addition, the SPS hydrogel had higher solar modulation and visible light transmittance than the SPN hydrogel with the addition of other anionic surfactants such as sodium dodecyl sulfate (SDS). Therefore, compared with the traditional PNIPAm hydrogels, SPS composite hydrogels had the advantages of high solar modulation rate, linear temperature response and multi-stimulus color change, which provided a wider range of application scenarios for smart color-changing hydrogels.

Key words: hydrogels, sodium dodecylbenzene sulfonate, thermochromic, surfactants, phase change temperature, pH response

摘要：

以十二烷基苯磺酸钠（SDBS）和N-异丙基丙烯酰胺（NIPAm）为原料，通过自由基聚合法成功制备了具有温度和pH双刺激响应的复合变色水凝胶（SPS）。SPS水凝胶具有更高的温度敏感性，当变温区间为10~40℃时，复合水凝胶的可见光透光率随着环境温度呈现线性变化，变色前后太阳光调制率ΔT_sol高于85.78%。由于SDBS在酸性环境中（pH≤2）的溶解度大大降低，复合水凝胶兼具pH变色响应的功能。此外，SPS水凝胶比添加其他阴离子表面活性剂如十二烷基硫酸钠（SDS）的SPN水凝胶具有更高的太阳光调制能力和可见光透过率。因此，相对于传统的PNIPAm水凝胶，SPS复合水凝胶具有高太阳光调制率、线性温度响应和多刺激变色等优势，为智能变色水凝胶提供了更广泛的应用场景。

关键词: 水凝胶, 十二烷基苯磺酸钠, 热致变色, 表面活性剂, 相变温度, pH响应