Mechanical Tuning of Colloidal Gels

Colloidal gels are materials widely used in commercial products. They are comprised of weakly attractive particles that form a space-spanning network in a fluid medium. Being non-equilibrium materials, their configurations can be easily modified by mechanical means. I aim to present two ways that these gels can be modified to obtain the desired rheological properties. One way is by shearing the gel at formation to push the gel to form stronger networks, thereby increasing the shearing moduli of the gel, and also accelerating the process. The second way is by subjecting the gel to an ultrasonic wave. The ultrasonic wave exerts forces on the particles in the medium, causing a rearrangement of the network as well as reductions in the shearing moduli and viscosity, both at shorter and longer times.