3D-printed dual-polarity polymer composites for broad-spectrum Volatile Organic Compounds (VOC) Detection

Abstract Chemiresistive polymer composites have emerged as promising candidates for sensing volatile organic compounds (VOCs) due to their mechanical flexibility, solution processability, and tunable molecular interactions. In this work, we report a miscible dual-polarity polymer blend composed of hydrophilic polyvinyl alcohol (PVA) and hydrophobic cellulose acetate butyrate (CAB), reinforced with 3 wt.% multi-walled carbon nanotubes (MWCNTs), and fabricated via direct ink writing (DIW) to produce uniform and defect-free sensing films. This complementary blend architecture enables simultaneous hydrogen bonding and van der Waals interactions, facilitating the selective and reversible detection of both polar analytes (e.g., ethanol, ammonia) and non-polar analytes (e.g., toluene, benzene, hexane) under ambient conditions. The resulting DIW-printed sensors exhibit high signal-to-noise ratios (SNRs) (i.e., >500 for most analytes and exceeding 2000 for toluene at elevated concentrations) and detection limits as low as 10 ppm for ethanol and 25 ppm for non-polar VOCs, without requiring elevated operating temperatures. Optical (UV–Vis) and saturation studies confirm that analyte–polymer affinity, governed by the hydrophilic–hydrophobic balance and facilitated by the nanotube percolation, dictates both sensitivity and selectivity. This study integrates a scalable and compositionally tunable manufacturing strategy for ambient VOC detection that highlights the potential of additive manufacturing to create flexible, high-performance gas sensing platforms, especially useful for plant or human health.