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Abstract This paper investigates the electrical, morphological, and mechanical behavior of ultrathin layer-by-layer polyaniline/poly(vinyl sulfonic acid) (PANI/PVS) ultrathin films for ammonia gas sensing. Atomic force microscopy shows that the PANI/PVS surface's roughness increases almost linearly with the number of PANI/PVS bilayers, while the surface morphology varies from a rod-like structure to a film-like architecture. Impedance measurements and their representation by a Cole-Cole model confirm this transition at ~15 bilayers. The designed sensor shows low response time (< 1 min), an optimal operating frequency range (1–100 Hz), high stability and sensibility to ammonia (~ 98 kΩ/ppm), and low sensibility to strain (~ 3.6 kΩ/%). This study suggests that hopping carriers' concentration remains constant, and hopping carriers' mobility changes with the number of bilayers. The simultaneous analysis of morphology with complex impedance measurements is a strategy for enhancing the electrical performance of low-cost and flexible organic sensing devices.

Abstract This paper investigates the properties of the polyaniline (PANI) on açaí vegetable fiber (AVF), hereafter referred to as PANI-COATED:AVF. Scanning electron and atomic force microscopy showed that the incorporation of PANI produced a linear surface, while optical microscopy images showed that the semiconductor layer was flawed. The complex impedance measurements performed at room temperature indicated that the electrical properties of PANI were fully transferred to the PANI-COATED:AVF and that the Cole-Cole approach dominated over a frequency range from 1 Hz to 100 kHz. Thermogravimetric analysis revealed a thermal stability range of 0° to 300°C. Finally, the combination of PANI with AVF was a successful due to the ease of processing and obtaining semiconductor filaments with wide ranges of thermal and electrical stability. This article is a complement to another recently published [doi.org/10.1002/pc.27068].