Wen Weijia, Huang Xianxiang, Yang Shihe, Lu Kunquan, Sheng Ping
Department of Physics and Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Nat Mater. 2003 Nov;2(11):727-30. doi: 10.1038/nmat993. Epub 2003 Oct 5.
Electrorheology (ER) denotes the control of a material's flow properties (rheology) through an electric field. We have fabricated electrorheological suspensions of coated nanoparticles that show electrically controllable liquid-solid transitions. The solid state can reach a yield strength of 130 kPa, breaking the theoretical upper bound on conventional ER static yield stress that is derived on the general assumption that the dielectric and conductive responses of the component materials are linear. In this giant electrorheological (GER) effect, the static yield stress displays near-linear dependence on the electric field, in contrast to the quadratic variation usually observed. Our GER suspensions show low current density over a wide temperature range of 10-120 degrees C, with a reversible response time of <10 ms. Finite-element simulations, based on the model of saturation surface polarization in the contact regions of neighbouring particles, yield predictions in excellent agreement with experiment.
电流变学（ER）指的是通过电场来控制材料的流动特性（流变学）。我们制备了包覆纳米颗粒的电流变悬浮液，其呈现出电可控的液-固转变。固态可达到130 kPa的屈服强度，突破了传统电流变静态屈服应力的理论上限，该上限是基于组成材料的介电和导电响应为线性这一普遍假设推导得出的。在这种巨电流变（GER）效应中，静态屈服应力与电场呈现出近似线性的依赖关系，这与通常观察到的二次变化形成对比。我们的GER悬浮液在10 - 120摄氏度的宽温度范围内显示出低电流密度，可逆响应时间小于10毫秒。基于相邻颗粒接触区域的饱和表面极化模型进行的有限元模拟，所得预测结果与实验结果高度吻合。
