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

Abstract

Conductive polymer coatings were successfully adsorbed to hexagonal polyethylene terepthalate plate surfaces after silane coupling and sulfonation were performed to promote intermolecular adhesion. Conducting particle coatings were verified via scanning electron microscopy observation, contact angle and conductivity measurements. The original substrates and newly modified platelet particles were used to form liquid marbles and aggregates through both the traditional rolling and electrostatic transfer methods of water droplet encapsulation. These two methods were then compared for stability and efficacy. In the rolling method, liquid marbles or aggregates were successfully fabricated using the PET plates with and without conducting polymer coating. In the electrostatic transfer method, the uncoated particles were unable to be extracted from the particle bed. Conversely, coated conductive particles were readily transferred to a pendent droplet, thereby stabilising it. Stability of these liquid marbles was also investigated at various stages of this coating process. In addition to this, the force of extraction was calculated using the field model of Morrison allowing for calculation of the interparticle forces in the particle bed, demonstrating that interparticle forces, rather than gravity, dominate the resistance to particle transfer.