화학공학소재연구정보센터
Applied Surface Science, Vol.476, 1035-1048, 2019
Anti-reflective and superhydrophobic films prepared from a sol at different withdrawal speeds
A novel sol dip coating method was used to fabricate thin films on glass substrates. Increasing withdrawal speed (V-w) resulted in decreased optical transmittance of the film and an increase in the water contact angle. At withdrawal speed (V-w) of 1 mm/min, the synthesized films demonstrated antireflective (AR) properties with an average transmittance of 96.57 +/- 0.14%. However, when V-w was > 10 mm/min, superhydrophobic films (referred to as SuHyd) were obtained, and at V-w = 15 mm/min, the water contact angle of the fabricated superhydrophobic film was 161.20 +/- 0.69 degrees. The AR films were heat-treated at 200 degrees C for 2 h (referred to as AR200) and 550 degrees C for 4 h (referred to as AR550). The AR550 film manifested a superior omnidirectional antireflective property in comparison to AR200. The scanning electron microscopy image revealed that the surface of the produced AR films was flat and most of the pores were < 100 nm; however, the surface of the SuHyd film had large corrugations with pores of several hundred nanometers. The alignment of the produced holes and protrusions on the surface of AR550 film was observed by atomic force microscopy, and the surface roughness of the three films was in the order of AR550 < AR200 < SuHyd. A mechanism was proposed to explain the different properties of AR and SuHyd films produced at different withdrawal speeds.