Laser Scanning System for Hydrophilicity Mapping on Curved Surfaces

Contact angle measurement is the most common technique for examining surface hydrophilicity. This technique usually involves a camera to capture the side view of a droplet. However, it often overlooks the distribution of hydrophilicity over the entire sample surface. In this study, a novel laser scanning technique was developed to obtain hydrophilicity maps of a curved sample surface with a maximum area of 175 mm × 250 mm. Moreover, a rotational tracking mechanism enabled the system to measure the curved surface with a tilt angle range of ±15°. The experiments yielded hydrophilicity maps of a polyimide film and glass slides. The results indicated that the developed laser scanning system was able to accurately determine the quantitative contact angle, height, and tilt angle images on the curved sample surface.