EXTRA SEMINAR: Nonlinear Rheology of Dilute Colloidal Gels

Colloidal gels are particulate suspensions with arrested dynamics and complex rheology, which have been exploited in a host of technological applications from consumer industries to direct write assembly and microfluidics. The rheology of colloidal gels has also received considerable attention in the scientific community, from both experimental and theoretical standpoints. Previous studies have mainly focused on the linear viscoelasticity or steady shear rheology of these systems, exploring commonalities among the different classes of arrested suspensions under quiescent or steady flow conditions. However, colloidal gels are often subject to transient large-strain deformations during their processing and handling, and their rheology under such conditions has not been thoroughly investigated. In this talk, our recent efforts in characterizing the microstructural evolution and rheology of colloidal gels in transient, nonlinear deformations by quantitative confocal microscopy and rheometry will be presented. The talk will primarily focus on depletion systems but comparisons with other classes of colloidal gels will also be made when appropriate.