Fabrication of self-cleaning superhydrophobic silicone rubber insulator through laser texturing

Novel superhydrophobic carbon fiber/epoxy composites with anti-icing properties

Abstract: In this study, novel carbon fiber/epoxy (CF/EP) composites with anti-icing properties were made using a combination of octadecylamine modification and hard templating. First, the octadecylamine-modified epoxy resin was sprayed on the surface of CF/EP prepreg. Hierarchical micro/nanostructures were formed on the surfaces of the composites through hot pressing with aluminum templates that had been modified by sandblasting and anodizing. The resulting composites were superhydrophobic, with static contact angles of up to 155° and sliding angles as low as 8°. Superhydrophobicity was maintained after abrading with 400 grit SiC sandpaper. The anti-icing properties of the composites were quantified by measuring droplet freezing time and ice adhesion force. Compared to untreated CF/EP, the surface treatments used here increased the time to freeze a 5 μL surface droplet from 76 to 640 s at − 20 °C, and reduced ice adhesion strength from roughly 74 kPa to 50 kPa.

Analysis of Wettability Characteristics in the Absence of the Electric Field and Under HVDC using Designed and Implemented an Experimental Platform for Contact Angle Measurement

Abstract: In this study, the wettability characteristics of Poly (methyl methacrylate) (PMMA) dielectric material which is used in high voltage applications and outdoor electrical applications in the presence and absence of the electric field was investigated. Saltwater droplets with a conductivity of 135.9 mS/cm were dropped onto the surface of a 5-mm thick PMMA dielectric material placed between two aluminum plane electrodes with a distance of 10 mm between them, and then 10 kV was applied between two aluminum electrodes. In the developed and implemented experimental platform, contact angle measurements were carried out using image processing techniques to interpret the wettability behavior of dielectric materials in the absence of the electric field and under HVDC. Wettability is one of the concepts used in the analysis of surface properties of materials and encountered in many engineering and science fields. Within the scope of this study, it is aimed to observe and analyze the correlation between the wettability characteristics, droplet shape, and contact angle under an electric field which has an important place under the topic of materials in science and engineering. Experimental results show that the electric field and the droplet liquid properties affect the contact angle and droplet shape. It was observed that the contact angle values decreased in the presence of the electric field and the apex of the droplet shape becomes more acute under the electric field.

Biomimetics: lessons from nature--an overview.

Abstract: Nature has developed materials, objects and processes that function from the macroscale to the nanoscale. These have gone through evolution over 3.8Gyr. The emerging field of biomimetics allows one...

Self-cleaning transparent superhydrophobic coatings through simple sol–gel processing of fluoroalkylsilane

Abstract: Upon contact with a dusty superhydrophobic surface, moving spherical water drops collect the dust particles and eventually flow off the surface. Herein, we report a very simple one-step approach to fabricate transparent and self-cleaning superhydrophobic coatings via the sol–gel processing of long-chain fluoroalkylsilane. The coating surface exhibited a rough, wrinkled, hill-like morphology similar to the microstructure of the lotus leaf (rough micro-scale papillae), which is promising for superhydrophobicity. The air bags trapped in the rough, hill-like structure allow the water drops to take a round shape with a contact angle of 169°. These round water drops abruptly roll off the coating surface at less than 5° of tilting. No major or minor water-drop pinning was observed during the roll off. The dust-repellent (self-cleaning) property, plastron stability, and durability against water-jet impact were examined on the superhydrophobic coatings.

Advanced Icephobic Coatings

Abstract: Adhesion and excessive accumulation of atmospheric ice on the surface of exposed objects such as conductors of overhead power lines, cables and conductors in aluminum can have devastating economical and safety consequences as it was the case during the 1998 and 2007 ice storms in Canada and USA. Recent advances in the understanding of ice adhesion on various substrates and in materials science have spurred interest in developing new intrinsic icephobic materials. The aim of this paper is to review the most relevant research activities related to ice adhesion mechanisms and icephobic coating development during the recent years. This will allow a better comprehension of ice adhesion, and help determine more reliable and cost effective ways to develop icephobic coatings, In order to develop icephobic coatings three main groups of materials or surface treatment can be considered: (i) self-assembled monolayers with –CH3 or –CF3 groups oriented outward to the ice surface, (ii) coatings with a heterogeneous chem...

Facile creation of hierarchical PDMS microstructures with extreme underwater superoleophobicity for anti-oil application in microfluidic channels

Abstract: Composition modification and surface microstructures have been widely utilized in interface science to improve the surface performance. In this paper, we observed a significant improvement of oil contact angle (CA) from 66 ± 2° to 120 ± 4° by introducing a radical silanol group on a flat PDMS surface through oxygen plasma pretreatment. By combining surface microstructures and plasma modification, we produced three kinds of superoleophobic surfaces: 20 μm pitch micropillar arrays, 2.5 μm pitch micropillar arrays and gecko foot-like hierarchical microstructures. Among them, the hierarchical surface with high surface roughness showed extreme underwater superoleophobicity, which featured ultrahigh CA (175 ± 3°) and ultrasmall sliding angle (<1°). Quantitative measurements demonstrated that these superoleophobic surfaces exhibited distinct adhesive behaviors, by which they were interpreted as Wenzel's, Cassie's and the Lotus state, respectively. A microfluidic channel with superoleophobic microstructures was further created by novel curve-assisted imprint lithography, and the characterization based on anti-oil contamination applications was carried out and discussed. We believe that the superoleophobic surfaces will power broad applications in oil microdroplet transportation, anti-oil channels and droplet microfluidic systems.