The role of poroelastic diffusion in the transient wetting behavior of hydrogels
The role of poroelastic diffusion in the transient wetting behavior of hydrogels
复制标题
多孔弹性扩散在水凝胶瞬态润湿行为中的作用
DOI：
10.1039/d3sm01472j
复制
发表时间：
2024
期刊：
影响因子：
3.4
通讯作者：
Cho, H. Jeremy
中科院分区：
文献类型：
--
作者：
Kashani, Amir;Cho, H. Jeremy
水凝胶的润湿和吸水在许多应用中经常遇到。我们试图了解润湿行为如何受到水凝胶的时间依赖性溶胀的影响。我们测量了水滴在不同厚度的水凝胶上的前进接触角，其中较厚的凝胶吸收水更慢。我们还观察到，在阈值前进速度以上，水滴将在表面上坍缩成较低的接触角状态。我们假设，这种崩溃阈值速度是水的多孔弹性扩散到凝胶中和扩散液滴的推进，表面的厚度，和水的扩散到凝胶中之间的竞争的结果。取扩散和推进时间尺度的比率，得到具有凝胶厚度的Peclet数作为特征长度尺度。我们的研究结果表明，在大约40的佩克莱数以上，液滴将在所有凝胶厚度的表面上塌陷，证实了我们的假设。这项工作提供了简单的见解，了解一个复杂的时间依赖性润湿现象的广泛使用的水凝胶。
Wetting and water absorption of hydrogels is often encountered in many applications. We seek to understand how wetting behavior can be affected by the time-dependent swelling of hydrogels. We measured the advancing contact angles of water droplets on hydrogels of varying thicknesses where thicker gels absorbed water more slowly. We also observed that, above a threshold advancing speed, water droplets would collapse into a lower contact angle state on the surface. We hypothesized that this collapse threshold speed is a result of competition between the poroelastic diffusion of water into the gel and the advance of the spreading droplet, the thickness of the surface, and the diffusion of water into the gel. Taking the ratio of the diffusion and advancing timescales results in a Peclet number with gel thickness as a characteristic length scale. Our results show that above a Peclet number of around 40, droplets will collapse on the surface across all gel thicknesses, confirming our hypothesis. This work provides simple insight to understand a complex time-dependent wetting phenomenon for a widely used hydrogel.