Coaxially electrospun PCDA-ZnO nanofibrous membranes with UV protection for high-temperature reversible thermochromism and colorimetric response to lactic acid

Various colorimetric sensing materials have been developed based on polydiacetylene (PDA), however, their sensing performance is limited by conventional low-temperature responsiveness and irreversibility. This study integrates a conventional PDA monomer, 10, 12-pentacosadiynoic acid (PCDA), with ZnO to fabricate core-shell structural PCDA-ZnO nanofibrous membranes by coaxial electrospinning technology. Here, PCDA-ZnO membranes demonstrated a thermochromic range of 100–210 °C, with reversibility observed below 170 °C. Additionally, the PCDA in the core is protected from short-term ultraviolet (UV) exposure by the inclusion of UV absorbers, ZnO, in the shell layer, thus preventing discoloration during storage. The coordination bond between polymerized PCDA (poly(PCDA)) and ZnO endows the nanofibrous membranes with the response capability to lactic acid solutions. The sensitivity of PCDA-ZnO membranes to lactic acid solutions fluctuates according to the ZnO concentration. Special high-performance polyarylene ether nitrile (PEN) was employed as the substrate material for PCDA to fabricated shell component, which enhances the stability of nanofibrous membranes under high-temperature, and corrosion, while also regulating the maximum reversible thermochromic temperature of the PCDA-ZnO membrane. The developed core-shell PCDA-ZnO nanofibrous membranes enhance the colorimetric response efficacy of PDA-based colorimetric sensors.