MXene-powered flexible smart windows for sustained bending performance

Abstract

Ti3C2Tx MXene is renowned for its high conductivity and flexibility, making it ideal for various applications. This study focuses on developing flexible and durable Polymer-dispersed liquid crystal (PDLC) based smart windows using Ti3C2Tx MXene-coated PET films, demonstrating sustained bending performance over 10,000 cycles. The fabrication process involved spin-coating of MXene dispersion (average flakes size ∼400 nm) on PET film to fabricate flexible transparent conductive electrodes (TCE) having a sheet resistance (Rs) of ∼550 Ω.sq.−1 and a transmittance of ∼80 % (at 550 nm). PDLC mixture containing liquid crystals and NOA65 monomer were sandwiched within MXene electrodes to prepare PDLC-based smart windows having a transmittance of ∼75 %. UV-cured polymer contributes to mechanical stability, while the Ti3C2Tx MXene electrodes impart electrical conductivity to the smart windows. The MXene electrodes demonstrate remarkable flexibility as evidenced by a minimal change in resistance, with a strain of 0.8 % resulting in a 0.7 % change in relative resistance (∆R/Ro) at a bending radius of ∼7.5 mm. The durability of flexible smart windows was investigated till 10000 bending cycles (bending radius of ∼9.5 mm). After sustained bending the smart films maintain ON-state transmittance in the 70–75 % range. These smart windows exhibit a variation of <5 % in ΔT (difference between OFF and ON-state transmittance) and the contrast ratio after 10000 bending cycles. These smart windows feature rapid switching time (ON/OFF) along with low power consumption of ∼8 Wm−2.