Enhancing Spontaneous Droplet Motion on Structured Surfaces with Tailored Wedge Design

Abstract

Spontaneous liquid transport has a wide variety of applications, including fog harvesting, microfluidics, and water‐oil separation. Understanding of the droplet movement dynamics on structured surfaces is essential for enhancing the transport performance. In this work, a theoretical model describing the movement process of droplets on surfaces with prescribed wedge shapes is developed. Agreement is observed between the predictions from the model and experimental results. Through theoretical analysis and quantitative comparison between the transport performance of different wedge shapes, the factors affecting the movement process are identified and guidelines for wedge shape optimization for spontaneous droplet transport are provided.

Bioinspired materials for droplet manipulation: Principles, methods and applications

“…Inspired by the anisotropy and wedge‐shaped structure in Figure 5a (ii), a wedge‐shaped SLIPS with nanostructures was produced, which could realize the self‐driven transport of droplets (Figure 5a, ⅲ). Apart from the classic wedge‐shaped structure, an optimized wedge shape was developed by Wang et al 75 for water transport. The great feature of the presented wedge model was that it consisted of a curve described by equations instead of a straight line.…”

Bioinspired materials for water-harvesting: focusing on microstructure designs and the improvement of sustainability

“…On the wedge-shaped patterned surface, the generated Laplace pressure allows the droplet to move from the wedge-shaped tip to the wedge-shaped wide end. [85][86][87][88] Song et al 89 combined PDMS and graphene (PDMS/G) to design a smart surface with a sharp shape that could be used for water collection, proving that the geometric pattern and wettability coordination were the key to the directional movement of the droplets. They used spin coating to prepare a superhydrophobic PDMS/G layer on a superhydrophilic glass substrate.…”

Directional Self-Transportation of Droplets on Superwetting Wedge-Shaped Surface in Air and Underliquid Environments

“…Intelligent droplet manipulation on a well-designed track has attracted interest in current technologies such as microfluidics operation, , microreactor technology, , interface catalysis, , and enhancement of heat and mass transfer. , High-rate and long-distance droplet movement on an open surface has significant practical benefits. − For example, the thickness of liquid film on condensing surfaces could be reduced through rapid directional movement of liquids, thus improving the heat transfer efficiency for a condensing process . The droplet movement process could be optimized by designing interfacial structure and character of surface toward reducing energy consumption and increasing droplet transport efficiency. − …”