Continuously fabricated transparent conductive polycarbonate/carbon nanotube nanocomposite films for switchable thermochromic applications

Abstract

Flexible transparent conductive films (TCFs) have attracted more and more attention because of their wide range of potential applications in optical and electronic devices. Industrial-scale manufacturing of high-performance TCFs is a challenge for a wide range of applications. Here, TCFs based on polycarbonate (PC) film successively coated with multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) are continuously fabricated by a combined spraying and roll-to-roll (R2R) technique. Moreover, such a continuous and scalable method is programmable and fully automated. The synergism between the successively sprayed MWNTs and SWNTs significantly enhances the conductivity and electrical homogeneity of the TCFs. Furthermore, such a film (i.e., PM₁S₁) still retains its high transmittance (82% at 550 nm), which is only decreased by 6% compared with the PC film. More importantly, no obvious decrease in the conductivity of the TCFs was detected after 1000 cycles of repeated bending, indicating their excellent mechanical flexibility. In addition, due to the synergistic effect, the adhesion and good environmental resistance have been significantly improved. With these advantages, the as-fabricated TCFs show great potential for application in flexible smart windows with switchable thermochromic properties. The proposed technique in this study is an effective approach for fabricating large-scale carbon nanotube/polymer based TCFs, which are promising for a wide variety of practical applications.