Effect of Ionic Strength and Surface Charge on Capillary-Driven Colloidal Self-Assembly and Deposition

Particle-particle and particle-substrate interactions play crucial role in convective self-assembly. The systematic study of varying surface charge and ionic strength is performed, altering the quality of particle thin film deposited. Increase in surface charge helps to obtain broader monolayer window. Monolayers were observed over wide range of deposition velocities compare with control silica suspension. Using confocal microscopy we were able to analyze the structural changes in coatings at different salt concentrations. Particle-particle screening at higher volume fraction is considerable, and using DLVO theory we have explained the possible mechanism for different crystallization speeds observed at different salt concentrations.