Hydrophobicity transfer from silicone rubber to adhering pollutants and its effect on insulator performance

Although the transfer of hydrophobicity to the outer surface of the pollution on silicone rubber insulators is found to be a slow process, the findings of this work indicate that its completion is not necessary to achieve near-full benefit. It is proposed that the techniques used for these studies can be readily adopted to quantify the effect of different types of pollutants and of the size plus shape of water drops on partially hydrophobic surfaces. Further, these experimental findings can help to establish an internationally accepted artificial pollution test for silicone rubber insulators and coatings. For such insulation in service, it is concluded that the average value of the contact angle of such water drops that had been evenly positioned along its length would be the most useful parameter when assessing the partially hydrophobic state of these adhering pollutants