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Developed by scientists in Poland, the new coating uses transparent silicone-epoxy modified with functionalized octaspherosilicates. The researchers have created five samples, each with a different combination of chemicals, and have found that ice adhesion was reduced by up to 43%, with freezing delay time growing by up to 70 times.
A group of scientists from Poland has developed a novel anti-icing coating for PV panels.
The novel coating is based on transparent silicone-epoxy modified with either two or three functionalized octaspherosilicates (OSS). Octaspherosilicates are a class of organosilicon compounds with a customizable structure that can enhance anti-icing properties.
“The formation and accumulation of snow and ice on the panels can obstruct light and thus minimize or even stop power production,” said the researchers. “Coatings could completely or partially replace the deicing methods used in the industry, which are inefficient. There are no reports in the literature on the use of similar chemical modifications of resins and polymer coatings, let alone transparent ones.”
The group created five different coating samples and started with a silicone-epoxy hybrid resin. The OSSs were made in a flask with 20 g of OSSs, 200 ml of toluene, and changing amounts of olefins, depending on the tested compound. Two weight percent (2 wt%) of the OSS were then integrated into the resin. The coating was applied to samples using the spin coating method.
Two of the samples had two olefins – OSS1 had allyl methacrylate (MA) and vinyl trimethoxysilane (VTMOS) at a molar ratio of 4:4; while OSS2 had MA and hexene (HEX) at a molar ratio of 6:2. Three samples had three olefins – OSS3 had allyl-glycidyl ether (AGE), octene (OCT) and octadecene (OD) at a ratio of 4:2:2; OSS4 had AGE, allyl – octafluoropentyl ether (AOFP) and OD at a ratio of 5:1:2; and OSS5 had AGE, AOFP and OD at a ratio of 4:2:2. In addition a sixth reference (REF) sample used an unmodified silicone-epoxy coating.
“The icephobic properties were discussed by determining an ice adhesion (IA) and a freezing delay time of water droplets (FDT),” explained the scientists. “The chemical modifications of silicone-epoxy coatings with bi- and tri-functional octaspherosilicates yielded auspicious results. In each case, the modification improved anti-icing properties. The reduction of IA and improvement of FDT compared to the unmodified sample was observed.”
While the REF sample had an FDT of three minutes (min) and an IA of 178 kilopascals (kPa), OSS 1 had over 210 min and 102 kPa, respectively. OSS 2 performed at 32 min and 150 kPa, while OSS3 showed over 210 min and 118 kPa. Finally, OSS4 had an FDT of over 210 min and an IA of 163 KpA, while OSS5 had 39 min and 157 kPa.
“Among the silicone-epoxy coatings tested, OSS1 and OSS3 samples showed the highest anti-icing properties. These coatings exhibited the lowest ice adhesion and the longest freezing delay time of water droplets,” the academics said. “However, a slightly lower IA value was obtained for the coating modified with OSS1. Thus, it can be concluded that the sample with this additive resulted in the highest anti-icing performance, with a 43% IA reduction and a 70 times increase in FDT value compared to the unmodified coating.”
The group also emphasized that the coatings can be potentially applied to photovoltaic panels, “since the conducted modification did not affect the optical properties of the investigated coatings.”
Their findings were presented in “Anti-icing transparent coatings modified with bi- and tri-functional octaspherosilicates for photovoltaic panels,” published in Colloids and Surfaces A: Physicochemical and Engineering Aspects. The research was conducted by scientists from Poland’s Warsaw University of Technology, Technology Partners Foundation, Military University of Technology, and Adam Mickiewicz University in Poznan. |
