Contactless Discharge-Driven Droplet Motion on a Nonslippery Polymer Surface

Abstract

Droplet manipulation is the cornerstone of many modern technologies. It is still challenging to drive the droplet motion on nonslippery surfaces flexibly. We present a droplet manipulation method on nonslippery polymer surfaces based on the corona discharge. With the corona discharge of two-needle electrodes with opposite polarities, the droplet's charge polarity can be switched, which results in the directionally droplet transport on a charged polymer surface with the oscillation. Here, such droplet behaviors are presented in detail. Dependence of the motion on the critical distance and driving distance between the droplet and the needle electrode is revealed. The driving mechanism is verified by experiments and simulations. This work enriches the droplet manipulation techniques on nonslippery surfaces for various applications, such as combinatory chemistry, biochemical, and medical detection.

Electrification of water: From basics to applications

“…In an example shown in Figure 4e, a water droplet is positively charged by dragging it on insulating substrates and therefore the droplet could be repulsively driven by a positively charged glass rod 107 . Similarly, the droplets, charged by means of conduction electrification, can also be attractively or repulsively manipulated by a guiding electrode with different polarities of applied voltages 108,109 . Additionally, through the elegant design of the surface charge distribution, a surface charge printing technology, eliminating the need for an electrode, could transport water droplets in a directed, long‐range, and self‐propelled fashion on superhydrophobic surfaces (Figure 4f).…”

“…107 Similarly, the droplets, charged by means of conduction electrification, can also be attractively or repulsively manipulated by a guiding electrode with different polarities of applied voltages. 108,109 Additionally, through the elegant design of the surface charge distribution, a surface charge printing technology, eliminating the need for an electrode, could transport water droplets in a directed, long-range, and self-propelled fashion on superhydrophobic surfaces (Figure 4f). 12 Despite the achievement of versatile droplet transport by the application of electricity alone, the seamless combination of electricity with other physical effects provides a high level of flexibility and freedom for droplet transport, which can markedly extend the scope of applications and perform tasks that may be otherwise impossible with the use of electricity alone.…”

Triboelectric ‘electrostatic tweezers’ for manipulating droplets on lubricated slippery surfaces prepared by femtosecond laser processing

“…Therefore, noncontact droplet manipulation is required in high-standard application scenarios. The existing methods of contactless droplet manipulation include passive and active methods [14,15]. Passive methods rely on designing a geometric gradient structure, chemical gradient, or wettability gradient [16][17][18][19].…”

Controllable Manipulation of Large‐Volume Droplet on Non‐Slippery Surfaces Based on Triboelectric Contactless Charge Injection

“…For example, the contact between magnetic nanoparticles and droplet during magnetic response processes could contaminate the droplets, light-induced surface tension gradients might fail to drive large-volume droplets fast enough, and thermal driving would probably cause partial evaporation of the droplets, which might affect the accuracy of bioassays and medical analysis. In comparison, electric-based approaches such as high-voltage (HV) electric field control [25,26] and electrowetting on dielectric (EWOD), [27,28] may open a promising avenue for droplet manipulation due to their inherent advantages of high spatiotemporal accuracy and greater maneuverability.…”