Hydrophobicity level detection of superhydrophobic glass-composite coatings based on a fibre-hole-fibre structure

A fibre-hole-fibre structure (FHFS) embedded within glass-fibre reinforce polymer (GFRP) is proposed for monitoring the hydrophobicity level of superhydrophobic GFRP coatings. Monitoring changes in the optical power transmission through the FHFS allows the detection of water droplets within a hole positioned in the middle of the optical fibre. The relationship between the hydrophobicity level of the GFRP coating and the transmitted optical power is analysed for different hole sizes. Using a proof-of-concept experimental setup based on a series of FHFSs with different hole dimensions, the proposed approach effectively identifies hydrophobicity levels, allowing the detection of eventual material failures and worn coatings with reduced hydrophobicity.