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机构地区:[1]北京师范大学化学学院,北京100875 [2]北京工商大学化学与环境工程学院,北京100048
出 处:《化学学报》2009年第15期1737-1742,共6页Acta Chimica Sinica
基 金:国家自然科学基金(No.20673014)资助项目
摘 要:在40Hz~110MHz频率范围对NaA沸石堆积体系和聚苯乙烯-聚吡咯悬浮液进行了介电测量.两类体系分别在105和107Hz表现出因界面极化产生的弛豫.利用Hanai理论解析两类体系的介电谱,发现解析体积分数与实测体积分数之间存在与体系的浓度相关的明显差异.通过分析Wagner原始模型阐明了差异的原因,指出了分散相粒子相互作用力与差异程度间的内在联系,从介电角度为胶体分散系中粒子统计排列方式的确定提供了判定依据:当分散系浓度高于临界值时,其最可取粒子统计排列模式为六方最密型;低于临界值后,排列模式随浓度的降低逐渐向简单立方型转变.NaA zeolite stacking systems and. polystyrene-polypyrrole suspensions were measured by di- electric spectroscopy in a frequency range from 40 Hz to 110 MHz. An obvious dielectric relaxation aroused from interfacial polarization was observed, at 105 Hz in the NaA zeolite stacking systems and 107 Hz in polystyrene-polypyrrole suspensions. According to dielectric analysis by Hanai's theory, the' obvious gap between the actual volume fraction and analyzed volume fraction was found. Moreover, the difference de- gree depended on the actual concentration of the dispersion system. By analyzing the original Wagner's model, the physical meaning of the analyzed volume fraction was clarified, and interaction among the dis- persed particles is responsible to the difference degree between the two volume fractions. As a result, a di- electric analysis way was offered to confirm the statistic arrangement pattern of particles (SAPP) in a colloid dispersion system. When the actual concentration is above the critical value, the optimum SAPP is a hexa- hedral stacking pattern. With the concentration decreasing, the optimum SAPP transits to the simple cubic stacking pattern.
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