Spontaneous Mosaics of Charge Formed by Liquid Evaporation

Abstract

Electrostatics is an old area of scientific research that over the years lagged behind most other areas of natural sciences. [1] Despite the great technological advances, even most basic questions like "what causes surfaces to charge?" or "how do dielectrics transfer charge?" are still matter of debate. [1c] This is also contemplated by the persistent controversy regarding the negative potential displayed by hydrophobic surfaces in contact with water, [2] which is revisited from time to time. [3] In fact, this widespread lack of understanding is responsible for triggering many industrial accidents, it costs billions of dollars to the electronic industry and restricts the appropriate development of important electrostatic technologies. [3e] For most systems, the outcome of contacting surfaces, in thermodynamic equilibrium or not, it is a net charge. In fact, electrified solid and liquid substances are easily formed either in natural or anthropic environments. Everyday activities or

The emerging chemistry of self-electrified water interfaces

“…A consequence of the Maxwell-Wagner effect is the production of electric mosaics 12 in any heterogeneous material, dividing its surface into domains of distinct electric charge. A related effect is the modulation of water surface charge under three-phase contact where the junction or contact potential depends on pH-dependent contact potential difference, contributing to water surface charge in various experimental environments.…”

“…62 An investigation by scanning probe microscopy 63 revealed polymer electrification by water ion injection into amorphous polymers and the formation of charge mosaics during water drying on a polymer surface. 12 Charge in water within other media produces interesting electro-hydrodynamic effects with relevant applications, like programmed water transport on charge-printed surfaces. 37 Summing up, many electrification mechanisms have been identified in different systems.…”

“…An investigation by scanning probe microscopy 63 revealed polymer electrification by water ion injection into amorphous polymers and the formation of charge mosaics during water drying on a polymer surface. 12…”

Quantifying nanoscale charge density features of contact-charged surfaces with an FEM/KPFM-hybrid approach

“…Contact electrification, the transfer of electric charge between objects during contact, is a ubiquitous and widely studied phenomenon, yet poorly understood [1]. Surprisingly, the charge transfer between insulators can be heterogeneous-correlated charge regions with sizes ranging from nanometers to centimeters are found on surfaces after contact [2][3][4][5]. KPFM has proven invaluable for addressing these features at the nanoscale, allowing one to measure a voltage map that is caused by the surface charge [5][6][7].…”

Microscale Bipolar Charge Distributions on Surfaces after Liquid Wetting and Evaporation in an Electric Field

“…Very recently, Moreira et al used Kelvin force microscopy (KFM) to show that the evaporation of liquids can lead to the development of bipolar charge and charge mosaics on insulator surfaces . This result is intriguing, but the process by which liquid evaporation leads to the formation of bipolar charge patterns has not yet been clarified.…”