A novel low-voltage fast-response electrically controlled dimming film based on fluorinated PDLC for smart window applications

A fluorinated polymer dispersed liquid crystal (PDLC) film with low operating voltage and high contrast ratio was successfully fabricated via the ultraviolet-initiated polymerization induced phase separation method. Effects of chemical structure and weight ratio of fluorinated monomers on the properties of PDLC films were systematically investigated through characterization of electro-optical response, micro morphology, optical spectrum and thermal analysis. Compared with the primitive sample, the addition of fluorinated monomers effectively improves the electro-optical properties of the film. The threshold voltage (Vth) is decreased by 39.7 % from 6.3 V to 3.8 V and the saturation voltage is reduced by 30 % from 15.8 V to 11.8 V for a 20 mu m-thick film. Besides, the contrast ratio is improved to 110. Meanwhile, its thermal stability and hydrophobic property are also improved. Additionally, due to the abundance of C-O and C-F bonds in these compounds and the porous structure, the prepared film allows for transmittance modulation of sunlight. This research is anticipated to provide an innovative approach to optimize the performance of PDLC films for practical applications.