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Main Authors: Zhao, Weiwei, Qian, Wenjie, Xu, Chang, Xu, Qin
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.10480
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author Zhao, Weiwei
Qian, Wenjie
Xu, Chang
Xu, Qin
author_facet Zhao, Weiwei
Qian, Wenjie
Xu, Chang
Xu, Qin
contents We report an experimental investigation of the spontaneous motion of liquid droplets on soft gels with a crosslinking gradient. By systematically adjusting the spatial difference in crosslinking density, we observed that millimeter-sized liquid droplets moved along the gradient of elastic modulus and even climbed tilted slopes against gravity. Unlike the wetting dynamics of micro-droplets, which are governed by elastocapillary effects, we demonstrated that the observed spontaneous movements of millimeter-sized droplets were attributed to the surface energy difference resulting from the variation in crosslinking density. Using {\em in-situ} confocal microscopy imaging, we analyzed the viscoelastic dissipation induced by the moving wetting ridges near dynamic contact lines. Based on the relationship between the crosslinking density and surface energy of soft gels, our findings reveal a new method for controlling droplet dynamics at soft and dissipative interfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2407_10480
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spontaneous Motion of Liquid Droplets on Soft Gradient Surfaces
Zhao, Weiwei
Qian, Wenjie
Xu, Chang
Xu, Qin
Soft Condensed Matter
We report an experimental investigation of the spontaneous motion of liquid droplets on soft gels with a crosslinking gradient. By systematically adjusting the spatial difference in crosslinking density, we observed that millimeter-sized liquid droplets moved along the gradient of elastic modulus and even climbed tilted slopes against gravity. Unlike the wetting dynamics of micro-droplets, which are governed by elastocapillary effects, we demonstrated that the observed spontaneous movements of millimeter-sized droplets were attributed to the surface energy difference resulting from the variation in crosslinking density. Using {\em in-situ} confocal microscopy imaging, we analyzed the viscoelastic dissipation induced by the moving wetting ridges near dynamic contact lines. Based on the relationship between the crosslinking density and surface energy of soft gels, our findings reveal a new method for controlling droplet dynamics at soft and dissipative interfaces.
title Spontaneous Motion of Liquid Droplets on Soft Gradient Surfaces
topic Soft Condensed Matter
url https://arxiv.org/abs/2407.10480