Controlling the Partial Coalescence of Particle-stabilized Droplets David Harbottle and Ilona Kretzschmar Department of Chemical Engineering, City College of New York, NY 10031 Partial Coalescence: a coalescence event in which pinch-off occurs creating a smaller daughter droplet. Pinch-off is governed by the rates of horizontal and vertical collapse, which in the case of particle-laden droplets is controlled by droplet rheology.
Drop at rest
Film rupture
Capillary stretching
Neck thinning
Pinch-off
Both particle-laden and particle-stabilized droplets are to be considered. The role of particle concentration, size, surface charge and wettability on the transition from partial to complete coalescence will be studied. 0.4
Partial coalescence can be suppressed through (i) impedance of horizontal collapse by means of particle network interaction (jamming) and (ii) dampening of the propagating capillary wave.
Drop size reduction ratio (d/di)
Drop size reduction ratio (d/di)
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Solids concentration (wt%)
Increasing particle concentration (low electrolyte concentration)
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We have been able to show that particle concentration and charge influence the transition condition (left) which is directly related to droplet rheology. Our next goal will be to elucidate the effect of particle size for particle-laden droplets and wettability for particlestabilized droplets.
