Influence of particle size on extraction from a charged bed – toward liquid marble formation

Abstract

Larger particles are more readily extracted from an advancing bed of charged particles owing to decreased interparticle cohesion.

Formation of liquid marbles & aggregates: rolling and electrostatic formation using conductive hexagonal plates

“…The low conductivity of the uncoated PET plates allows for only dielectrophoretic extraction forces as opposed to the much stronger Coulombic force, diminishing the total extraction force placed on the particles. 23,40,41,54 Conversely, the PPy coated particles were readily extracted from the particle bed (Fig. 5), due to their greater conductivity (Table 2); behaviour consistent with previous work examining the impact of particle conductivity on electrostatic particle extraction.…”

“…Electrostatic particle coating of pendent water droplets was carried out following the same regime as previously reported. 22,23,25,28,35 An electrically-earthed 5 mL pendent tap water droplet was positioned above a stainless steel plate, upon which a microscope slide with concave glass inset and bed of PET plates were mounted. The bed was prepared by placing a small quantity of platelets on the slide.…”

“…In recent years an alternative method of liquid marble formation has been reported, utilising an electric field. [22][23][24] This process features contactless delivery of the particles to a pendent droplet and allows for substantial control of the droplet volume with no risk of coalescence. Furthermore, it allows for the use of hydrophilic particles to form particle-stabilised aggregates, where the particles are internalised in the droplet resulting in a metastable structure.…”

“…25,27 However, some of the limitations of this particular method are that the particles must overcome interparticle forces, such as cohesion and friction in order to be extracted to the pendent droplet, which may be aided by increased conductivity and particle size. 22,23,28 To this end, the viability of relatively large conductive platelets, compared to those previously studied, 22,23,28 to stabilise a droplet will be investigated.…”

“…21,34 These newly synthesised coatings will be investigated with respect to their viability as liquid marble stabilisers using both the traditional rolling 1,4,21 and the contactless electrostatic method of liquid marble formation, during which their electrostatic transfer behaviour will be investigated. 22,23,25,28,35…”