Transition Between Solid-like and Liquid-like States in Soft Silica Suspensions

The influences of silica volume fraction, electrolyte concentration and pH value upon the stress dependence of elastic modulus G′and viscous modulus G″ were investigated. The results show that the suspension transforms from a liquid-like state to a solid-like state with increasing the volume fraction of silica. Such a solid-like state can be transformed back into a liquid-like state under the application of a larger stress. At the higher volume fraction, the larger critical stress is required to induce the transition from solid-like to liquid-like state. As the electrolyte concentration decreases or pH value increases, the inter-particle force increases, which causes the state transition to occur at a higher stress.