POS4-0322
Directional Liquid Transport on Position-Selective Wettability-Patterned Surfaces
Topic
S4. Colloids, Interfaces, and Molecular Assemblies for Functional Soft Materials
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Seoyoung Kim (Department of Polymer Engineering, Dankook University, Yongin, Republic of Korea)
Co-Author(s)
Abstract
In this study, we present a patterned surface engineered for wettability control, facilitating self-driven transport of small liquid volumes for various applications such as microfluidics, water harvesting, and biomedical engineering. Unbalanced surface tension is generated on a substrate due to chemically modified patterns, which causes small water droplets to self-propel along predefined pathways without the need for external energy sources. A hydrophilic channel, which gradually widens and is surrounded by a hydrophobic area, was designed to guide droplet movement along its pathway. Furthermore, nanoscale trenches were created on the hydrophilic channel, aligned perpendicularly to where the droplets would travel. Thus, the water droplet sequentially encounters the recessed trenches during its movement along the pathway. A colloidal suspension of polystyrene particles was added to integrate a separation function into this passive transport system. During droplet transport, particles are directed towards the recessed trenches, allowing geometric confinement to facilitate their trapping and alignment. To explore size-dependent particle capture and ordered placement, sequential trenches with different widths were used, since trench width dictates the size of polystyrene particles that can be trapped. This design aims to sort and separate particles by size. Future work will involve switching from rigid silicon wafers to polydimethylsiloxane (PDMS), a soft, deformable polymer, to create a flexible interfacial platform. By combining wettability-guided droplet transport with geometry-assisted colloidal trapping, this study proposes a passive strategy for liquid manipulation, particle patterning, and size-based separation without external energy input
