物理交联刚果红—聚乙烯醇凝胶膜的敏感特性研究

以二甲基亚砜(DMSO)水溶液为溶剂,采用冷冻—解冻法制备高度透明的物理交联聚乙烯醇(PVA)凝胶膜,将该膜在刚果红溶液中浸泡,制备了物理交联刚果红—聚乙烯醇(PCGR—PVA)凝胶膜。利用紫外—可见光谱法测试该凝胶膜的pH敏感特性,并与化学交联的刚果红—聚乙烯醇(CCGR—PVA)凝胶膜做了对比分析。结果表明:PCGR—PVA和CCGR—PVA凝胶膜均具有良好的pH敏感性,在pH为0.29~4.33范围内对pH呈较好的线性响应,PCGR—PVA凝胶膜的灵敏度更高。PCGR—PVA凝胶膜的响应时间在弱酸中小于10 s,在强酸中小于200 s。表明PCGR—PVA凝胶是优异的pH传感材料。

Study on sensitive characteristics of physically crosslinked congo red-PVA gel membrane

High transparent physically crosslinked polyvinyl alcohol （PVA） gel membranes are prepared by freezing/thawing method in dimethyl sulfoxide （DMSO）aqueous solution, then the membranes are immersed in the congo red solution and congo red-PVA（PCGR-PVA） gels are fabricated. And compared with CCGR-PVA, UV/Vis spectroscopy studies of PCGR-PVA and CCGR-PVA gel membranes indicate that both of them show good pH sensitivity and good linear response in pH 0.29 -4.33, whereas the latter is more sensitive to pH changes compared with CCGR-PVA membranes. The response time of PCGR-PVA gel membranes is less than 10 s in weak acid,it is less than 200 s in strong acid. The results show that PCGR-PVA gel is an excellent pH sensing material.