Superhydrophobic Candle Soot Coating Directly Deposited on Aluminum Substrate with Enhanced Robustness

Hussein Ali Hussein,Sabah Ibrahim Wais,Khedir R Khedir

doi:10.3390/coatings12020202

Abstract

In this study, superhydrophobic surfaces were developed by using a simple and environmentally friendly technique. The nano-network of candle soot (CS) as the byproduct of incomplete combustion of paraffin candle was directly coated onto both smooth and micro-rough aluminum (Al) substrates for various time periods of deposition. The simple technique of mechanical sanding was used to impart micro-rough structures onto Al substrates using different sandpaper grit sizes. The scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and X-ray diffraction (XRD) techniques were used to characterize the morphology and chemistry of the prepared surfaces. Wetting analysis of the prepared surfaces was performed by measuring both water droplet contact angle (CA) and sliding angle (SA). The prepared coatings showed superhydrophobic properties with high CAs and low SAs for CS surfaces coated on roughened Al substrates. Moreover, the robustness of the prepared surfaces was tested by continuous impingement of water droplets onto their surfaces from various heights. Post-testing wetting analysis showed that the micro-nano surfaces of candle soot coated on micro roughened Al substrates demonstrated improved robustness. These surfaces could be useful for self-cleaning, anti-corrosion and anti-icing applications.

Highlights

For the last two decades, there has been a significant amount of research devoted to the fabrication of surfaces with super water-repellent properties known as superhydrophobic surfaces due to their wide range of industrial applications [1,2,3,4]
The thickness of the coating significantly increased with the inthe best of our knowledge, this is the first time in which the side-view scanning electron microscopy (SEM) images have crease in the time of deposition as shown in the side-view SEM images presented in Figure been reported for candle soot (CS) coatings in terms of time deposition
Candle soot directly coated onto smooth Al substrate showed superhydrophobic properties but with a material directly coated onto smooth Al substrate showed superhydrophobic properties lack of robustness

Summary

Introduction

For the last two decades, there has been a significant amount of research devoted to the fabrication of surfaces with super water-repellent properties known as superhydrophobic surfaces due to their wide range of industrial applications [1,2,3,4]. The lotus leaf is an example of a plant that has a unique way to survive in its wetting and moisture environment, which is exemplified by its super repellant property in terms of water. Superhydrophobic surfaces have a water contact angle of more than 150◦ and a sliding angle of less than 10◦ [6,7,8,9]. The key to this property is the surface roughness and low surface energy of the surface. For low surface energy materials such as polymers, roughness alone is sufficient for obtaining the superhydrophobic property

Methods

Results

Conclusion