Gravity effect of silica and polystyrene particles on deposition pattern control and particle size distribution on hydrophobic surfaces
Journal
Journal of Industrial and Engineering Chemistry
Journal Volume
106
Pages
214-224
Date Issued
2022
Author(s)
Abstract
Ring-like residual deposits are often observed after drying suspension droplets on surfaces. That introduces a crucial defect in practical applications, such as ink-jet printing that requires a uniform deposit. In this study, depositions after drying sessile/pendant droplets with silica/polystyrene particles were examined to identify the effect of gravitational sedimentation of particles on self-pinning and deposition pattern. The suspension droplet with larger polystyrene (or silica) particles would trigger the self-pinning at larger (or smaller) particle concentrations. The deposition pattern of pendant drops with silica particles is hill-like. This is due to the large density difference between silica and water to induce high sedimentation velocity, and the particles would precipitate and aggregate along the air–liquid interface to form a hollow shell deposit. The depositions for suspensions with bi-dispersed particles, the larger silica particles would accumulate at the bottom of the deposit due to the higher sedimentation velocity, in contrast to the well-mixed in the deposits for bi-dispersed polystyrene particles. The sedimentation and capillary flow velocities were calculated and discussed. These new findings reveal that the particle density (gravity effect) can be used to adjust the sedimentation velocity to control the deposition morphology and particle size distribution even to suppress the coffee-ring effect. ? 2021 The Korean Society of Industrial and Engineering Chemistry
Subjects
Coffee ring effect
Deposition pattern
Drop
Evaporation
Gravity
Sedimentation
Air
Drops
Hydrophobicity
Ink
Particle size
Particle size analysis
Phase interfaces
Polystyrenes
Silica
Size distribution
Solutions
Surface chemistry
Suspensions (fluids)
Velocity
Coffee rings
Deposition patterns
Gravity effects
Particles-size distributions
Polystyrene particle
Ring effect
Sedimentation velocities
Self-pinning
Silica particles
Deposits
Type
journal article