A dynamic Cassie-Baxter modelElectronic supplementary information (ESI) available: It contains details of device fabrication, expanded discussion of the dynamic contact angle measurements, definition and calculation of the line solid fraction λs and comparison of 3-D data to existing models. See DOI: 10.1039/c4sm02651a

Contact-angle hysteresis of a liquid suspended on surface microstructures, namely in a Cassie-Baxter state, is determined mainly by the receding contact line although not fully understood. Existing modified Cassie-Baxter models predict some but not most experimental data in the literature. Noting th...

Full description

Saved in:
Bibliographic Details
Main Authors: Liu, Tingyi Leo, Chen, Zhiyu, Kim, Chang-Jin
Format: Article
Language:English
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Contact-angle hysteresis of a liquid suspended on surface microstructures, namely in a Cassie-Baxter state, is determined mainly by the receding contact line although not fully understood. Existing modified Cassie-Baxter models predict some but not most experimental data in the literature. Noting that most models were based on the two-dimensional (2-D) principle whereas the experiments were under three-dimensional (3-D) conditions, here we develop a 2-D experiment. While 3-D experiments measure the receding contact lines averaged over space and time, 2-D experiments eliminate the spatial averaging and can further eliminate the temporal averaging by high-speed visualization. The resulting details of the contact line motion lead us to propose a 2-D model, which incorporates the contact-line friction. The new 2-D model matches the 2-D experimental results excellently while all existing models show significant deviation. By introducing a line solid fraction term, the 2-D model is further generalized to a 3-D model, which successfully predicts a wide range of 3-D data in the literature regardless of their distinct microstructures and receding modes. A new model predicts the receding contact angle of a liquid suspended on microstructures for a wide range of data in the literature regardless of their distinct patterns and receding modes.
ISSN:1744-683X
1744-6848
DOI:10.1039/c4sm02651a