Surface Evolution of Pigment Coating

•     We studied the surface evolution of coating by using a random deposition model of particles. In order to capture the real coating structure development, we included a volume exclusion effect to represent particle-particle interaction, and a levelling effect to represent surface tension effect. In this study we investigated three cases: (1) random deposition on a flat surface, (2) random deposition on a flat surface with levelling, and (3) random deposition on a rough surface with levelling.When plotting in logarithmic scale, the roughness initially increased linearly with average number of particles deposited for all three cases but reached saturation after a certain amount of deposited particles. The result resembles a ballistic deposition process where agglomerates are developed over the surface due to lateral growth. Even a flat, uniform surface creates roughness during random deposition of particles.Autocorrelation analysis showed that the correlation length continues to increase with the number of particles deposited. The aggregated structures were easily seen in the autocorrelation function.Experimental and simulated data on the rough surface were compared and they were in agreement, confirming that the coating process is essentially a random process with some local correlation in the length scale of a typical fibre width. 

Ämnesord

NATURVETENSKAP  -- Annan naturvetenskap (hsv//swe)

NATURAL SCIENCES  -- Other Natural Sciences (hsv//eng)

Nyckelord

Microstructure

Films

Particle Processing

Simulation

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