Improving the Hydrophobicity of ZnO by PTFE Incorporation

Abstract

The objective of the present study is to obtain a zinc oxide-(ZnO-) based superhydrophobic surface in a simple and cost-effective manner. Chemical immersion deposition being simple and economical has been adopted to develop modified ZnO coating on glass substrate. Several modifications of ZnO like treatment with alkanoic acid (stearic acid) and fluoroalkylsilane to tune the surface wettability (hydrophobicity) were attempted. The effect of thermal treatment on the hydrophobic performance was also studied. It was observed that thermal treatment at 70• C for 16 hrs followed by immersion in stearic acid resulted in high water contact angle (WCA), that is, a superhydrophobic surface. Thus, a modified ZnO superhydrophobic surface involves the consumption of large amount of electrical energy and time. Hence, the alternate involved the incorporation of low surface energy fluoropolymer polytetrafluoroethylene (PTFE) in the ZnO coating. The immersion deposited ZnO-PTFE composite coating on modification with either stearic acid or fluoroalkylsilane resulted in a better superhydrophobic surface. The coatings were characterized using Scanning Electron Microscope (SEM) for the surface morphology. It was found that microstructure of the coating was influenced by the additives employed. A flower-like morphology comprising of needle-like structure arranged in a radial manner was exhibited by the superhydrophobic coating.

Water‐Stable Sulfide Solid Electrolyte Membranes Directly Applicable in All‐Solid‐State Batteries Enabled by Superhydrophobic Li+‐Conducting Protection Layer

“…Bare Li 6 PS 5 Cl membrane without any coating is hydrophobic with a water SCA of 118.0°, due to the incorporation of low-surfaceenergy fluoropolymer polytetrafluoroethylene (PTFE) as binders. [26] If the coating layer contains only LATP nanoparticles (Ratio TEOS + PFDTES /LATP = 0:1), the hydrophobicity of the Li 6 PS 5 Cl membrane was not improved (SCA = 117.8°). Once the reactants of F-POS were introduced into the coating layer (Ratio TEOS + PFDTES /LATP = 1:1), the water SCA increased significantly to 148.2°, conforming the important role of F-POS in the mixture.…”

A fast and effective approach for reversible wetting-dewetting transitions on ZnO nanowires

“…Surface roughness modification includes surface patterning 26 , or micro/nano structuring 27 which includes strict growth conditions and complex processing techniques. However, the ZnO surface energy modification include low surface energy chemical coatings to enhance ZnO hydrophobicity 24 28 29 30 , which involves harsh chemical treatment. Moreover, the extent to which such approaches are effective depends upon the nature of the surface material.…”

New Approaches to Increasing the Superhydrophobicity of Coatings Based on ZnO and TiO2

“…In the normal state, a zinc oxide (wurtzite crystal structure) surface is highly hydrophilic (wetting contact angle less than 5 • ) and even prolonged annealing at 350 • C does not lead to noticeable changes. [1] This is due to the characteristics of the interaction of water molecules with a ZnO surface [2]: a strong covalent bond between oxygen of the water molecule and the surface of the zinc atom, as well as the formation of O-H groups between the hydrogen of the water molecule and the surface oxygen atoms. As for the properties of a TiO 2 surface, this is more complicated.…”