Kinetics of evaporation of colloidal dispersion drops on inclined surfaces

Evaporation of colloidal dispersion drops leaves a deposit pattern where more particles are accumulated at the edge, popularly known as the coffee-ring effect. Such patterns formed from dried sessile drops are azimuthally symmetric. When the substrate is inclined, the symmetry of the patterns is altered due to the influence of gravity. This is reflected in the changes in (i) pinning/depinning dynamics of the drop, (ii) the strength of the evaporation-driven flows, and (iii) ultimately, the lifetime of the drop. We present a systematic investigation of the kinetics of evaporation of particle-laden drops on hydrophilic inclined solid substrates. The angle of inclination of the substrate (& phi;) is varied from 0 & DEG; to 90 & DEG;. The temporal analysis of the drop shape profile is carried out to unearth the contribution of different processes to kinetics of evaporation of drops on inclined surfaces. The influence of particle concentration, drop volume, and angle of inclination on the kinetics of evaporation and the resulting deposit patterns are discussed.

Automated summary

The evaporation of colloidal dispersion drops on inclined solid substrates leads to the formation of the coffee-ring effect, where more particles are accumulated at the edge. The symmetry of the patterns formed from dried drops is altered when the substrate is inclined due to gravity's influence. We conducted a systematic investigation on the kinetics of evaporation of particle-laden drops on hydrophilic inclined solid substrates, varying the angle of inclination and analyzing the contribution of different processes to the evaporation kinetics.