Liquid-Vapor

Phase Change

Icephobic

Surface

Droplet

Dynamics

Research: Research

Liquid-Vapor Phase Change

Research: 文字

Research: Research

Condensation

Condensation can be enhanced by using micro/nanostructured surfaces. However, no surface was able to avoid the flooding-induced condensation heat transfer deterioration at high ΔTsub (the degree to which the condenser surface is cooled relative to the surrounding vapor). Here, we propose a brand-new three-dimensional (3D) hybrid surface to prevent the condensation surface from flooding.

Ching-Wen Lo, Yu-Cheng Chu, Ming-Han Yen, and Ming-Chang Lu, Enhancing Condensation Heat Transfer on Three-Dimensional Hybrid Surfaces, Joule, 3, 2806-2823, 2019.
Ming-Chang Lu, Chien-Chang Lin, Ching-Wen Lo, Cheng-Wei Huang, and Chi-Chuan Wang, Superhydrophobic Si Nanowires for Enhanced Condensation Heat Transfer, International Journal of Heat and Mass Transfer, 111, pp. 614-623, 2017.

Controlled Nucleation

Nucleation of condensation is an intrinsically random process because the energy barriers to nucleation on an ordinary surface are randomly distributed. Researchers have reported that superhydrophobic surfaces with hydrophilic patterns could spatially control the nucleation. However, hydrophilic patterns are not favorable for promoting dropwise condensation. The aim of this work is to spatially control the nucleation of condensation without using any hydrophilic patterns.

Ching-Wen Lo, Chi-Chuan Wang and Ming-Chang Lu, Spatial Control of Heterogeneous Nucleation on the Superhydrophobic Nanowire Array, Advanced Functional Materials, 24, 9, pp. 1211-1217, 2014.

Surface Engineering

Micro/nano (two-tier) structures are often employed to achieve dropwise condensation on superhydrophobic surface. However, the effect of roughness-scale on the dynamics of the condensation process was not fully comprehensive. This work aims to clarify the roughness-scale effect on condensation subject to superhydrophobic surfaces.

Ching-Wen Lo, Chi-Chuan Wang and Ming-Chang Lu, Scale Effect on Dropwise Condensation on Superhydrophobic Surfaces, ACS Applied Materials & Interfaces, 6, 16, pp. 14353–14359, 2014.

Go back

Icephobic Surface

Research: 文字

Controlled Ice Formation

Utilizing superhydrophobic surfaces for anti-icing is getting more and more attention nowadays. However, superhydrophobic surfaces lose their icephobic property when ice covers the whole surface area. In this work, we propose a way to alleviate the impact of icing on a surface by spatially controlling the ice formation at its early stage and remedying the ice issue locally and immediately on the solid surface.

Ching-Wen Lo, Venkataraman Sahoo and Ming-Chang Lu, Control of Ice Formation, ACS Nano, 11, pp. 2665-2674, 2017. (Featured by X-OL, Nanowerk and Phys.org)

Anti-icing & De-icing

Ice formation on various surfaces causes catastrophic consequences or enormous economic losses. Superhydrophobic surfaces with extreme water repellency were applied for removing ice efficiently; however, their practical applications are hindered by the fabrication of the complicated micro/nanostructures of the surfaces. In this work, we proposed using hydrophilic nylon-6 nanofiber membrane coating for enhancing deicing.

Ching-Wen Lo, Jia-Xiong Li, and Ming-Chang Lu, Frosting and Defrosting on the Hydrophilic Nylon-6 Nanofiber Membrane–Coated Surfaces, Applied Thermal Engineering, 184, 116300, 2021.

Go back

Research: Research

Droplet Dynamics

Research: 文字

Elongated Bouncing Drop

Droplets impacting on a solid surface and the movement of liquid droplets on a solid surface are common phenomena in our daily life. These phenomena are also widely seen in many industrial systems. However, a high mobile liquid droplet has never been realized on a hot surface with concurrent contact boiling and the Leidenfrost effect (the so-called Janus thermal state). It is very challenging to simultaneously reduce the contact time and enhance the droplet mobility in the Janus state because of bubbling on a solid surface. In this work, we overcome these difficulties and achieve a large reduction of contact time in the Janus state.

Venkataraman Sahoo, Ching-Wen Lo and Ming-Chang Lu, Leidenfrost suppression and contact time reduction of a drop impacting on silicon nanowire array-coated surfaces, International Journal of Heat and Mass Transfer, 148, 118980, 2020.
Venkataraman Sahoo, Chu-Yao Chou, Ching-Wen Lo and Ming-Chang Lu, Elongated Bouncing and Reduced Contact Time of a Drop in the Janus State, Langmuir, 34, pp. 10874-10879, 2018.

Anti-Fouling

Fouling causes numerous adverse effects on various types of systems. In addition, clean fouling on a solid surface is cost-intensive and time-consuming. Superhydrophobic (SHB) surfaces with a water-repellent property can potentially be used for antifouling. However, SHB surfaces lose their antifouling property at high temperatures because of the failure of the hydrophobic coating on them. Nevertheless, there are numerous applications being operated at high temperatures. Thus, a surface exhibiting antifouling characteristic over a wide temperature range is required. In this study, we demonstrate that a double re-entrant pillar (DRP) array surface possesses a wide-temperature antifouling characteristic. Although the silicon dioxide top surface of the pillar is hydrophilic, the upward surface tension force from the DRPs prevents the impacting droplets from penetrating the pillar array. Thus, the impacting droplets bounce back from the surface without leaving residues on it at temperatures from 25 to 560°C. By contrast, the impurities of the impacting droplets are retained on an SHB surface composed of a silicon nanowire array at various temperatures. The wide-temperature antifouling property of the DRP surface can be used for preventing fouling in many industrial systems.

Chung-Te Huang, Meng-Shiue Lee, Ching-Wen Lo, Wensyang Hsu, and Ming-Chang Lu, Wide Temperature Antifouling Characteristic of a Double Re-Entrant Pillar Array Surface, International Journal of Heat and Mass Transfer, 175, pp. 121178, 2021.
Chung-Te Huang, Ching-Wen Lo, and Ming-Chang Lu, Reducing Contact Time of Droplets Impacting Superheated Hydrophobic Surfaces, Small, DOI: 10.1002/smll.202106704, 2022.