Wissenschaftliche und technische Sammelreferate

Bühl, Alfons

doi:10.1007/bf01431549

Cited by 15 publications

(1 citation statement)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This charging can be easily observed: a Teflon slide withdrawn from a pool of pure water acquires a sufficiently strong charge to attract, for example, a stream of water running from a tap. The phenomenon is herein termed “dewetting electricity” to emphasize its dynamic three-phase line nature, which distinguishes it from other electrostatic charging phenomena, such as truly dry solid contact charging and spray electrification (also referred to as balloelectricity or waterfall electrification). − …”

Section: Introductionmentioning

confidence: 99%

Electrostatic Surface Charging by Water Dewetting

Knorr,

Rosselli,

Nelles

2024

Langmuir

View full text Add to dashboard Cite

Water dewetting generates static electricity. We reviewed historical experiments of this phenomenon, and we studied the charging of polymer slides and metal electrode supported polymer films withdrawn vertically from a pool of aqueous solutions. For pure water, charging was negative and surface charge densities increased with the speed of dewetting, which we explain by the thermally activated entrainment of nanometer-sized water droplets or clusters charged by unbalanced adsorbed electric double-layer ions. Surface charge densities increased for reduced polymer film thickness following a power law, which we explain by reduced discharge of the entrained water volumes. At low salinity c ≲ 10 μM, charging was proportional to electrokinetic interfacial charge densities: the negative charging was increased for alkaline solutions and for most salts at μM concentrations and the charge polarity was inversed to positive for a cationic surfactant, a salt with a highly positively charged cation, and for a strong acid at approximately pH 4. Charging was reduced again for c ≳ 100 μM, especially at high dewetting speeds and for chaotropic ions, which we explain by the entrainment of larger and more discharged droplets. We determined adsorption energies of the charged water clusters on the dewetted surface from thermally stimulated discharge of the charged polymer slides and we show that the surface charge distribution, imaged by charged toner powders and measured microscopically by Kelvin probe force microscopy, is a record of the dewetting process that provides spatial and kinetic information about the three-phase contact line motion.

show abstract