Study on New Chargeable Photoelectric Conversion Effect in Composite System of Tungstic Acid and Organic Polymer

考虑到氧、碳和氢的电负性分别为3.4、2.6和2.2，我们可以解释添加剂（包括O-C- h结构）光致变色增强的原因。在O-C键中，氧比碳更强烈地吸引电子。因此，如果碳形成像O-C-H这样的键，碳和氢之间的键强度将比氧和碳之间的键强度弱得多。在这种情况下，氢可以很容易地被光生成的孔氧化释放。另一方面，如果碳与烷基成键，则碳与烷基之间的键比O-C-H结构中碳与氢之间的键强，因为烷基是电子供体。酮类和羧酸之所以没有表现出光致变色增强，是因为它们的O-C键旁边没有氢。b.我们通过时间分辨表面波测量研究了钨酸、明胶和硅胶凝胶化过程中的表面波性质。波数指数chi（ω -kappa^2, 1.5和1.0分别表示表面张力和弹性波）的变化明显地表现出异常。钨酸的Chi在溶胶状态下约为1.4，在胶凝点迅速降至1.0。明胶在溶胶状态下的Chi约为1.4（与钨酸相同），在凝胶点后逐渐降低。另一方面，凝胶的chi在凝胶点后保持在1.5附近。c.我们研究了凝胶的脱水过程，这对溶胶-凝胶法的应用很重要，我们发现凝胶中溶剂和聚合物网络的相互作用对凝胶脱水过程的特征有很大的影响。

a.We could explain the origin of the photochromic enhancement by the additives, including the O-C-H structure, taking account of the electronegativities of oxygen, carbon and hydrogen that have the values rhof 3.4,2.6 and 2.2, respectively, In the O-C bond, the oxygen will more strongly attract the electron than the carbon. Thus, if carbon makes bonds such as O-C-H, the bond strength between the carbon and hydrogen will be much weaker than that between the oxygen and carbon. In such a case, the hydrogen may be easily released with oxidation by the photogenerated hole. On the other hand, if the carbon bonds with an alkyl group, the bond between the carbon and the alkyl group is stronger than that between the carbon and the hydrogen in the O-C-H structure since the alkyl group is an electron donor. It has also been consistently explained that ketones and carboxylic acids do not show the photochromic enhancement because they do not have hydrogen next to the O-C bond.b.We studied the properties of surface waves during the gelation process of tungstic acid and gelatin and silica gel by the time resolved surface wave measurements. The anomaly is clearly shown in the change of the wave number exponent chi(omega-kappa^2 , the values 1.5 and 1.0 indicate surface tension and elastic wave, respectively). chi of the tungstic acid was about 1.4 in the sol state and rapidly decreased to 1.0 at the gelation point. chi of gelatin was about 1.4 (same as tungstic acid) in the sol state and decreased gradually after the gelation point. On the other side, chi of silica gel remained near 1.5 after the gelation point.c.We have studied dehydration process of gels, which are improtant to use the sol-gel method, and have found that the feature of the dehydration process has been much affected by the interaction between solvent and polymer network in the gels.