Effect of Ionic Strength and Surface Charge on Convective Deposition

Langmuir. 2015 Nov 17;31(45):12348-53. doi: 10.1021/acs.langmuir.5b03109. Epub 2015 Nov 4.

Abstract

Particle-particle and particle-substrate interactions play a crucial role in capillary driven convective self-assembly for continuous deposition of particles. This systematic study demonstrates the nontrivial effects of varying surface charge and ionic strength of monosized silica microspheres in water on the quality of the deposited monolayer. Increase in particle surface charge results a broader range of parameters that result in monolayer deposition which can be explained considering the particle-substrate electrostatic repulsion in solution. Resulting changes in the coating morphology and microstructure at different solution conditions were observed using confocal microscopy enabling correlation of order to disorder transitions with relative particle stability. These results, in part, may explain similar results seen by Muangnapoh et al., 2013 in vibration-assisted convective deposition.