A Fully Bio-Based Bamboo Paper Fluorescent Sensor with Excellent Water Resistance and Reprocessability

Abstract Traditional paper-based fluorescent sensors are limited by poor water resistance, lack of reusability, and reliance on complex conjugated polymers. Herein, a fully bio-based paper fluorescent sensor was developed via a dynamic-exchange reaction between carbamate groups of polyhydroxyurethane (PHU) and hydroxyl groups of bamboo paper (Bp). The PHU prepolymer was applied onto the Bp and then thermally cured to achieve interfacial covalent linkages. The sensor exhibits excellent mechanical properties, with a tensile strength of 4.3 MPa. The introduction of long aliphatic hydrophobic segments into the sensor increases the water contact angle from 0° to 93°, significantly improving water resistance. Notably, the sensor shows 2.3 times higher fluorescence than Bp, attributed to the molecular binding between the carbamate and hydroxyl group of Bp. The sensor effectively detects Fe3+ ions, erythromycin, and tobramycin. This work offers a novel strategy for developing green, sustainable, and high-performance paper-based fluorescent sensors.