A Simple Way to Achieve Self-Cleaning Surfaces with Unique Antifouling Property

Abstract

Self-cleaning surfaces may have wide applications such as microfluidic devices, lab-on-a-chip, sensors, microreactors, air purification, and antimicrobial fields. In this article, by using a combination of femtosecond (fs) laser irradiation and fluorination technique, self-cleaning stainless steel surfaces with unique antifouling property were obtained. New insight is developed through a detailed analysis of the antifouling behavior of the self-cleaning surfaces. The surface free energy and its polar and disperse components were calculated by using the Owens–Wendt-–Rabel–Kaelble (OWRK) method. X-ray photoelectron spectroscopy was employed to analyse the surface elemental compositions and functional groups. The antifouling property of the surface was recorded by using a high speed camera. Water sliding angles (SAs) were reduced by fluorination treatment, resulting in low adhesive superhydrophobic surfaces with the self-cleaning property. The influences of micro/nanostructures, fluorination, and their combination on the surface free energy were investigated. The interaction process between water droplets and pollutants (inorganic and organic particles) on the treated surface was explored. The antifouling property of an optimized specimen (CA = 162° and SA = 1°) was tested and compared with the untreated sample.

Bio-Based Waterborne Polyurethane Coatings with High Transparency, Antismudge and Anticorrosive Properties

“…Different from the solvent-based system, the polar groups of −COOH were necessarily introduced by DMPA in this study to improve the water dispersibility and the stability of the waterborne coatings. Due to the adhesion of polar groups of −COOH with the polar contaminates from the oily marker, the oil-based inks were harder to remove from the waterborne coating surface than from the solvent-based coating surface . For the effect of cross-linking degree of coatings, it has been reported that increasing the cross-linking degree can resist ink penetration .…”

“…Due to the adhesion of polar groups of −COOH with the polar contaminates from the oily marker, the oil-based inks were harder to remove from the waterborne coating surface than from the solvent-based coating surface. 60 For the effect of cross-linking degree of coatings, it has been reported that increasing the cross-linking degree can resist ink penetration. 61 In this study, multifunctional polyol (e.g., castor oil with an average functionality of 2.7) and isocyanate (e.g., HDIT with functionalities of 3.0) were used to ensure coatings with a sufficient high crosslinking degree.…”

“…This greatly hinders the development of NP-GLIDE WPU coating. 39,40 At present, there are two basic ways to enhance the antismudge properties of NP-GLIDE WPU coating. One is to shield the polar hydrophilic groups by a lot of PDMS for improving the antismudge property.…”

“…The stability of WPU dispersion, however, might be greatly decreased by using excess PDMS, during both the procedures of dispersion preparation and dispersion storage. To stabilize the dispersion, hydrophilic groups (−COOH) need to be typically introduced; however, this would go against the antismudge property of coating. , The balance between the stability of dispersion and the antismudge property of coating is difficult to control. Another technique is to reduce the cross-linking degree of the PU prepolymer for improving the stability of WPU dispersion.…”

“…Besides, the polar groups on the coating surface are easy to adhere to various types of pollutants. This greatly hinders the development of NP-GLIDE WPU coating. , …”