(354e) Next Generation Polymer-Based Hybrid Materials for Targeted Trace Gas Detection

With the rapid pace of industrialization and technological advancement, the emission of toxic gases such as volatile organic compounds (VOCs), greenhouse gases (GHGs), and nitrogen and sulfur oxides (NOx, SOx) has increased significantly. These pollutants originate from diverse sources, including fossil fuel combustion, chemical manufacturing, mining, landfills, and forest fires. Prolonged exposure to such analytes poses serious health hazards to humans and ecosystems. As a result, there is a growing need for gas sensors that are real-time, portable, wearable, and miniaturized—while maintaining high sensitivity, selectivity, stability, and processability.

Traditional gas detection techniques like gas chromatography, infrared spectrometry, and Raman spectroscopy offer high accuracy but are hindered by their bulkiness, high cost, and the need for trained personnel and lengthy analysis times. Emerging gas sensors based on sensing materials are broadly categorized as inorganic (e.g., metal oxide semiconductors) and organic (e.g., conjugated polymers). Inorganic materials provide excellent sensitivity and low detection limits but suffer from high operating temperatures, baseline drift, short lifetimes, and poor selectivity. Organic materials like polymers and graphene offer advantages such as mechanical flexibility and room-temperature operation, albeit at the expense of sensitivity. Hybrid materials such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) attempt to combine these advantages but often struggle low selectivity, stability, and processing challenges.

This work offers a novel approach to tackling these challenges by exploring the potential of in-situ synthesized polymer-metal oxide hybrid composites for room temperature trace formaldehyde gas sensing, with a focus on environmental monitoring applications. By combining the high sensitivity of metal oxides with the tunable selectivity and flexibility of polymers, this study evaluates polyaniline (PANI) and its derivative, poly (2,5 dimethyl aniline) (P25DMA) composites with metal oxides, including In₂O₃ and NiO. These hybrids exhibit modulated morphology and synergistic interactions, enhancing sensing materials sensitivity and selectivity toward formaldehyde over common interferents such as benzene and acetaldehyde, without requiring elevated temperatures.

This approach offers a generalized framework for the development of low-power, high-performance sensing materials applicable to a wide range of analytes that can be integrated into miniaturized sensors systems. The resulting sensors hold promise for a wide range of critical applications, including environmental monitoring, industrial safety, non-invasive medical diagnostics, and food quality tracking.