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多酸的固体和材料化学是多酸化学的一个新兴领域和重要的发展方向,已经显示出广阔的应用前景,如Keggin型的钨磷酸、钼磷酸具有良好的质子导电性,已被制成质于导电膜,在固体修饰电极、电致变色材料及离子选择性电极方面也已得到实际应用.在各类多酸中,由于十聚钨酸阴离子W_(10)O_(32)~(4-)具有光致催化性质,对它的研究令人瞩目.但W_(10)O_(32)~(4-)在水溶液中不稳定,易转化为多种阴离子的平衡混合物,固态形式仅限于它的盐类(主要是有机胺盐).最近我们发现粉状白钨酸在聚乙烯醇(PVA)或其它高分子水溶液中有相当大的溶解度,可以得到稳定的十聚钨酸溶液,并进而得到含十聚钨酸的高分子薄膜.通过光谱鉴定和组成分析,证明了在聚乙烯醇存在下,十聚钨酸能以固态形式存在,而且这是首例十聚钨酸/高分子复合物.我们还研究了组成、湿度、光致变色对复合物薄膜导电性的影响.1 实验1.1 仪器与试剂TJ-270型红外光谱仪,UV-240型紫外可见光谱仪,LCT-2型差热分析仪,GGY125W荧光汞灯.薄膜电阻用四探针法在控制湿度及温度的体系中测定.复合物薄膜中WO_3,PVA及水的含量由热重分析法确定.粉状白钨酸(简写为WPTA,化学式WO_3·1.5H_2O)按文献[7]合成.
The solid and material chemistry of polyacids is an emerging field and an important development direction of polyacid chemistry. It has shown broad application prospects. For example, Keggin-type tungstophosphoric acid and molybdophosphoric acid have good proton conductivity and have been made into It has also been applied in the field of conductive films, solid modified electrodes, electrochromic materials and ion-selective electrodes.In all kinds of polyacids, due to the decatungstic acid anion W_ (10) O_ (32) ~ (4- ) Has attracted much attention due to its photocatalytic properties.However, W_ (10) O_ (32) ~ (4-) is unstable in aqueous solution and can be easily converted into a balanced mixture of many kinds of anions. The solid form is only limited to Of salts (mainly organic amine salts) Recently, we found that powdered tungstic acid has considerable solubility in polyvinyl alcohol (PVA) or other aqueous polymer solutions to provide a stable solution of decaturonic acid and further And obtain the polymer film containing decatched tungstic acid.Through spectral identification and composition analysis, it is proved that decametungstic acid can exist in solid state in the presence of polyvinyl alcohol, and this is the first decaturonic acid / polymer composite We also studied the composition, humidity, and photochromism of the composite thin Conductivity.1 Experimental 1.1 Instruments and reagents TJ-270 type infrared spectrometer, UV-240 type UV-Vis spectrometer, LCT-2 type differential thermal analyzer, GGY125W fluorescent mercury lamp. Thin film resistor with four probe method in the control of humidity And the temperature of the system.The content of WO_3, PVA and water in the composite film was determined by thermogravimetric analysis.The powdery tungstic acid (abbreviated as WPTA, chemical formula WO_3 · 1.5H_2O) was synthesized according to the literature [7].