Zhao X P, Duan X
Institute of Electrorheological Technology, Department of Applied Physics, Northwestern Polytechnical University, Xi'an, 710072, People's Republic of China.
J Colloid Interface Sci. 2002 Jul 15;251(2):376-80. doi: 10.1006/jcis.2002.8281.
A new type of organic/inorganic hybrid colloid, made of modified carboxylmethyl starch (CMS) and titanium oxide (TiO(2)), was synthesized by an in situ sol-gel technique. IR spectra analysis shows strong a interaction of functional groups between two components, whose dispersion is almost at the molecular level. Due to the highly active surfaces hybrid particles and their characteristic dielectric behavior in accordance with the previous theoretic calculation, the suspensions of hybrids in silicone oil display a remarkable ER effect. The static yield stress can be above 20 kPa (shear rate 5 S(-1)) under a direct current field of 4 kV/mm at room temperature, much higher than that of simple blends of starch and titanium dioxide. In the meanwhile, the temperature dependence and sedimentation stability were optimized. Based on existing experimental results, we propose that dielectric properties and surface (interface) activity are two necessary conditions fulfilling the requirement of high ER activity. The combination of both factors may effectively reduce the activation energy needed for ERF restructuring.
通过原位溶胶-凝胶技术合成了一种新型的由改性羧甲基淀粉（CMS）和二氧化钛（TiO₂）制成的有机/无机杂化胶体。红外光谱分析表明两种组分之间的官能团存在强烈相互作用，其分散几乎处于分子水平。由于杂化颗粒具有高活性表面以及与先前理论计算相符的特征介电行为，杂化物在硅油中的悬浮液表现出显著的电流变效应。在室温下4 kV/mm的直流电场下，静态屈服应力在剪切速率为5 s⁻¹时可高于20 kPa，远高于淀粉和二氧化钛简单混合物的屈服应力。同时，优化了温度依赖性和沉降稳定性。基于现有实验结果，我们提出介电性能和表面（界面）活性是满足高电流变活性要求的两个必要条件。这两个因素的结合可有效降低电流变体重组所需的活化能。
