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Updated: Jun 22, 2026
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One-Step Approach to Fabricating Polydimethylsiloxane Microfluidic Channels of Different Geometric Sections by Sequential Wet Etching Processes
Published on: September 13, 2018
Tunable open-channel microfluidics on soft poly(dimethylsiloxane) (PDMS) substrates with sinusoidal grooves
Krishnacharya Khare1, Junhao Zhou, Shu Yang
1Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 4, 2009
Summary
Wetting behavior on wrinkled surfaces depends on surface energy and groove depth. Deeper grooves enhance wetting anisotropy and can lead to spontaneous fluid imbibition, driven by capillary forces.
Area of Science:
- Materials Science
- Surface Science
- Fluid Dynamics
Background:
- Soft poly(dimethylsiloxane) (PDMS) substrates with 1D sinusoidal wrinkle patterns exhibit anisotropic wetting.
- Understanding fluid behavior on such patterned surfaces is crucial for microfluidics and material design.
Purpose of the Study:
- To investigate anisotropic wetting and fluid transport on wrinkled PDMS substrates.
- To determine the influence of surface energy and groove geometry on wetting behavior.
- To study the spontaneous imbibition of fluids into grooves.
Main Methods:
- Fabrication of PDMS substrates with tunable 1D sinusoidal wrinkle patterns.
- Experimental observation of liquid droplet morphology and contact angle anisotropy.
- Analysis of fluid imbibition dynamics using a force balance model.
Main Results:
- Wetting anisotropy increases with groove depth for hydrophobic surfaces (contact angle > 90°).
- Hydrophilic surfaces (contact angle < 90°) with deep grooves exhibit filament-like morphology.
- Spontaneous groove imbibition occurs beyond a threshold groove depth, following Washburn's law.
- Capillary force is identified as the primary driver for groove filling.
Conclusions:
- Groove geometry and surface wettability significantly control anisotropic wetting and fluid transport on wrinkled PDMS.
- The study provides insights into spontaneous fluid imbibition mechanisms in micro-grooves.
- Findings are relevant for designing microfluidic devices and controlling fluid behavior on patterned surfaces.
