Excellent ultraviolet‐blocking properties of chiral nematic liquid crystals

Abstract

AbstractWe report the evaluation of chiral nematic liquid crystal (CNLC) in blocking ultraviolet (UV). The CNLC was coated on a calcium fluoride substrate to measure the spectral transmittance, which was measured to detect the UV‐blocking effect of CNLC. The results show that CNLC could reduce UVB (290–320 nm) by 99.9% and UVA (320–400 nm) by 95.6%. The barrier effect of cake‐shaped semi‐solidified CNLC microspheres was further investigated, and it was found that cake‐shaped semi‐solidified CNLC microspheres could reduce UVB by 58.2% and UVA by 34.1%. This is due to the chemical absorption property of CNLC, which has UV‐absorbing functional groups such as the benzene rings. And the physical reflection properties of CNLC could periodically reflect a certain wavelength of light. Liquid crystal (LC) is a rich set of soft materials with rod‐like structures widely existing in nature, which is harmless to the human body and environment. Therefore, using CNLC's function of blocking UV, a new sunscreen can be developed.