Interaction of a particle bed with a droplet under an applied electric field

[摘要] Transport of dry solid particles to a liquid is relevant to a number of emerging applications, including 'liquid marbles'. We report experiments where the transport of dry particles to a pendent water droplet is driven by an external electric field. Both hydrophilic and hydrophobic materials (silica, PMMA) were studied. For silica particles (hydrophilic, poorly conductive), a critical applied voltage initiated transfer, in the form of a rapid 'avalanche' of a large number of particles. The particle-loaded drop then detached, producing a metastable spherical agglomerate. Pure PMMA particles did not display this 'avalanche' behaviour, and when added to silica particles, appeared to cause aggregation and change the nature of the transfer mechanism. This paper is largely devoted to the avalanche process, in which deformation of the drop and radial compaction of the particle bed due to the electric field are thought to have played a central role. Since no direct contact is required between the bed and the drop, we hope to produce liquid marble-type aggregates with layered structures incorporating hydrophilic particles, which has not previously been possible.

[发布机构] Centre for Advanced Particle Processing and Transportation, University of Newcastle, University Drive, Callaghan; NSW; 2308, Australia^1

[效力级别] 数学

[关键词] Avalanche process;Emerging applications;External electric field;Hydrophilic and hydrophobic;Hydrophilic particles;Layered Structures;Spherical agglomerates;Transfer mechanisms