Scaling Behavior of Colloidal Gel Elasticity in the Context of Dispersant Surface Activity
Fatemeh Khalkhal (Yale University), Chinedum Osuji (Yale University)
Complex Fluids: Suspensions, Emulsions, and Gels
Wed 9:00 - 10:30
Barus-Holley 160
Colloidal suspensions exhibit a diverse range of rheological properties from viscous liquid-like behavior at low concentrations to elastic solid-like behavior at high concentrations. The wide range of rheological behavior pledges multiple industrial applications in coatings, printing inks, food, biological systems, oil drilling, engine lubrication, and etc. If attractive forces are present between the particles, the suspensions will flocculate and demonstrate more complicated rheological behavior such as aging, shear thickening, slip and apparent yielding and etc. Upon the formation of aggregates, the suspensions experience instabilities that introduce experimental complications and can limit the application of these suspensions if are not properly addressed. On the other hand, by controlling the inter-particle interactions more efficient dispersion of colloidal suspensions can be obtained; addition of dispersing agents can provide steric/electrostatic stabilization and overcome the experimental complications due to undesirable aggregation. In this work, a set of model suspensions of weakly attractive carbon black particles has been prepared in base stock oil in presence of various dispersing agents. Robust adsorption isotherms were obtained from FTIR analysis and combined with rheological measurements to evaluate the adsorption efficiency of different surfactants. The results reveal the importance of rheological investigations coupled with accurate determinations of surface coverage and pave the way for design of new dispersants.