What is a typical effect of UV aging on hydrophobicity of polymer insulators?

• A. Hydrophobicity increases, reducing leakage
• B. Hydrophobicity is not affected
• C. Hydrophobicity is reduced, increasing leakage/tracking potential
• D. Hydrophobicity changes only color

Answer: (C)

UV aging degrades the surface chemistry of polymer insulators, weakening the hydrophobic layer that keeps water from sticking to the surface. Sunlight, ozone and weathering oxidize and break down the surface, reducing the migration or presence of hydrophobic compounds, so the surface becomes less water-repellent. In polluted, humid conditions, this means water spreads more readily, forming conductive paths that raise leakage current and increase the chance of tracking or surface flashover. The key effect is a loss of hydrophobicity, not an increase, even though color changes can occur.