Development of infrared-reducing coating from poly(3, 4-ethylenedioxythiophene) polystyrene sulfonate

The infrared- reducing coating is useful for reducing heat transfer from sunlight through windows. Transparent conductive oxides (TCO) such as fluorine tin oxide(FTO) have high optical transparency and NIR reflective properties making it suitablefor window coating. However, TCO is a required complex process to make thin-filmcoating and expensive. In this work, infrared (IR)-reducing glass coating employingpoly(3,4 ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was tested anddeveloped for heat reducing performance.Heat- insulating PEDOT: PSS thin film was prepared by adding tetraethylorthosilicate (TEOS) as a binder and applied using a wired bar coater. The optical andinfrared shielding performance of the coatings was investigated using an ultraviolet-visible-near-infrared (UV-VIS-NIR) spectrometer. The obtained film showed infraredshielding property with about 25 %reduction in the NIR region ) 750- 2500 nm (whilemaintaining high transparency in the visible region of over 85 .%The film also showedgood scratch resistance upon TEOS addition with the pencil hardness level of 3Hincreased from 6B level in that of the pristine film. Illumination test showed thata window coated with the developed film can attain the temperature reduction by about1.3-3.4 ºC compared to that of the uncoated glass. The wettability of the film was alsoexamined and the water contact angle results indicated that the coated film displayedmore hydrophilicity than that of the uncoated glass which may promote the waterwetting of the coated glass leading to facile cleaning.