NEW ELECTRORHEOLOGICAL FLUID - THEORY AND EXPERIMENT

We have fabricated novel doubly coated particles, with a conducting in ner layer and an insulating outer layer, for use in electrorheological fluids. Orders of magnitude enhancement in the yield stress is obtain ed by using such particles, when compared to that of bare particles or singly coated particles (with the insulating layer only). The measure d static yield stress agrees well with first-principles calculations, and supports a physical picture using electrostatic energy arguments f or an intuitive understanding of this large enhancement.