Controllable porosities of conjugated microporous polytriphenylamine enable high sensitivity toward trimethylamine at low temperatures

• • NaF-PTPA achieves a response (R) of 22 at 100 ppm TMA at 54 °C, a 5.5-fold enhancement over pure PTPA (R = 4), enabling reliable low-temperature detection for cold-chain food safety and clinical breath analysis. • • The sensor exhibits a low detection limit of 0.53 ppm, below the 5 ppm long-term exposure limit set by the American Conference of Governmental Industrial Hygienists (ACGIH), and sufficient for sub-ppm biomarker detection in chronic kidney disease. • • Long-term stability over 30 days at 54 °C with consistent performance indicates robust material durability, critical for continuous industrial monitoring without frequent recalibration. • • Tunable porosity via nanosilica templates and Hansen solubility parameters yields increased surface area and protonated –NH2+ sites, directly correlating with enhanced TMA adsorption and charge transfer, providing a design rule for next-generation chemiresistive sensors.