Hydrophobic and oleophobic sol‐gel coatings on glass substrates for usage at high temperatures

Abstract

The paper reports an optimized process to obtain transparent and highly hydrophobic sol‐gel coatings with further oleophobic behavior at high temperatures. Polyorganosiloxane sols were prepared incorporating an organic based precursor, 1H,1H,2H,2H Perfluorooctyltriethoxysilane (POTS), into a silica‐based hybrid sol and deposited on soda‐lime glass‐slides. The coating surfaces show high water contact angle (WCA) around 120 ± 1° and oil contact angle (OCA) of 70 ± 1° after curing at temperatures between 350 and 400°C. The coatings thickness changed between 300 and 2000 nm depending on sol composition and curing temperature. Easy‐to‐clean tests were performed, the results showing excellent anti‐stick and easy‐to‐clean properties compared to non‐coated samples. Atomic force microscopy (AFM) revealed the presence of rippled surfaces with morphology similar to “lotus leaf surface,” this explaining the properties. These hybrid fluoroalkylsilane sol‐gel coatings are a good alternative to provide anti‐stick and easy‐to‐clean properties to glass substrates being quite easy to scale up.

Progress in Studies of Surface Nanotextures and Coatings with Nanomaterials on Glass for Anti-Dust Functionality

“…Eren et al [ 97 ] used the sol-gel method to construct a lotus-leaf-like textured structure on a glass surface and confirmed the long-term durability of the coating through testing. Zhang et al [ 94 ] mixed silicone resin, ethanol, and silica nanoparticles to form a superhydrophobic coating, which was uniformly applied to the glass ( Figure 5 a).…”

Ag-enriched TiO2 nanocoating apposite for self-sanitizing/ self-sterilizing/ self-disinfecting of glass surfaces

“…The Ag–TiO 2 NCs thus exhibited an obvious red-shift in absorbance edge and a significant enhancement of light absorption in the region 300–1000 nm. This shift has been assigned to charge transfer transition between the electrons of Ag and TiO 2 at the interface via the surface plasmon resonance (SPR) effect of Ag because the Fermi level of Ag is located below the conduction band of TiO 2 [ 14 , 25 ]. It resulted in the formation of Schottky barrier acting as electron-trapping centre thereby escalating absorption wavelength, plunging bandgap energy, improving photocatalytic performance, and enhancing antibacterial activity [ 33 ].…”

“…An important advantage of sol-gel process is to achieve transparent hydrophobic and oleophobic coatings [ 24 ]. Very recently, sol-gel procedure has been widely used in the fabrication of anatase Ag–TiO 2 NCs [ 11 , [25] , [26] , [27] , [28] , [29] , [30] ]. While sol-gel process facilitates the fabrication of Ag–TiO 2 NCs thru phase purity and thermal stability; spin-coating technique provides film uniformity and thinness controllability; and thermal annealing provides superior crystallinity and defect manageability.…”

Preparation of a biomimetic superomniphobic hierarchical structure and analysis of droplet wettability

“…However, a solid surface with a single hydrophobic property does not meet the needs of actual complex functions, and other characteristics should be added to form a multifunctional composite surface. A hydrophobic surface with low adhesion property [21][22][23] has received increasing attention. Additionally, drag reduction, desorption, and self-cleaning [24][25][26][27] are in demand in transportation [28] and petrochemical [29] fields.…”