Surfactants Screen Slide Electrification

Fuente: arXiv
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Hauptverfasser: Li, Xiaomei, Ni, Zhongyuan, Zhou, Xiaoteng, Bauer, Lisa S., Diaz, Diego, Schäfer, Gabriele, Butt, Hans-Jürgen
Format: Preprint
Veröffentlicht: 2025
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author Li, Xiaomei
Ni, Zhongyuan
Zhou, Xiaoteng
Bauer, Lisa S.
Diaz, Diego
Schäfer, Gabriele
Butt, Hans-Jürgen
author_facet Li, Xiaomei
Ni, Zhongyuan
Zhou, Xiaoteng
Bauer, Lisa S.
Diaz, Diego
Schäfer, Gabriele
Butt, Hans-Jürgen
contents Water drops spontaneously accumulate charges when they move on hydrophobic dielectric surfaces by slide electrification. On the one hand, slide electrification generates electricity with possible applications on tiny devices. On the other hand, the potential of up to 1 KV generated by slide electrification alters wetting and drop motion. Therefore, it is important to know the factors that affect slide electrification. To find out how surfactants affect slide electrification, we measured drop charges of aqueous drops containing cationic CTAB, anionic SDS and neutral C8E3 sliding on different hydrophobic surfaces. The result is: addition of surfactant significantly reduces the spontaneous charging of moving water drops. Based on zeta potential measurements, confocal microscopy of deposited surface-active dyes and drop impact studies, we propose that several factors contribute to this suppression of charge separation: (1) Surfactants tend to lower the contact angles, which reduces charge separation. (2) Surfactant adsorption at the solid-liquid interface can reduce the density of primary ions, particularly for anionic surfactants. (3) Anionic and neutral surfactants are mostly transferred to the liquid-air interface at the rear of the sliding drop, retaining primary ions within the drop. (4) Deposited cationic surfactant directly reduces the charge of the drop.
format Preprint
id arxiv_https___arxiv_org_abs_2504_01084
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Surfactants Screen Slide Electrification
Li, Xiaomei
Ni, Zhongyuan
Zhou, Xiaoteng
Bauer, Lisa S.
Diaz, Diego
Schäfer, Gabriele
Butt, Hans-Jürgen
Soft Condensed Matter
Materials Science
Chemical Physics
Water drops spontaneously accumulate charges when they move on hydrophobic dielectric surfaces by slide electrification. On the one hand, slide electrification generates electricity with possible applications on tiny devices. On the other hand, the potential of up to 1 KV generated by slide electrification alters wetting and drop motion. Therefore, it is important to know the factors that affect slide electrification. To find out how surfactants affect slide electrification, we measured drop charges of aqueous drops containing cationic CTAB, anionic SDS and neutral C8E3 sliding on different hydrophobic surfaces. The result is: addition of surfactant significantly reduces the spontaneous charging of moving water drops. Based on zeta potential measurements, confocal microscopy of deposited surface-active dyes and drop impact studies, we propose that several factors contribute to this suppression of charge separation: (1) Surfactants tend to lower the contact angles, which reduces charge separation. (2) Surfactant adsorption at the solid-liquid interface can reduce the density of primary ions, particularly for anionic surfactants. (3) Anionic and neutral surfactants are mostly transferred to the liquid-air interface at the rear of the sliding drop, retaining primary ions within the drop. (4) Deposited cationic surfactant directly reduces the charge of the drop.
title Surfactants Screen Slide Electrification
topic Soft Condensed Matter
Materials Science
Chemical Physics
url https://arxiv.org/abs/2504.01084