Search

An array of chemiresistors based on conducting polymers was assembled for the differentiation of VCO. The chemiresistor sensors were fabricated through the potentiostatic electrodeposition of polyaniline, polypyrrole and poly (3-methylthiophene) on the gap separating two planar gold electrodes set on a Teflon substrate. The electrical resistance of the sensors were measured and observed to change when exposed to the headspace of oil samples. The sensor response was rapid and exhibited good reversibility and reproducibility. Different signals were obtained for each coconut oil sample and pattern recognition techniques were employed for the analysis of the data. The developed E-nose system was able to discriminate VCO from refined, bleached and deodorized coconut oil (RBDCO) and rancid VCO.

A graphene/polyaniline (rGO/PANi) nanocomposite was synthesized by solution blending method and deposited on to a nylon-6 membrane via vacuum assisted self-assembly (VASA) method to fabricate a flexible material applied as a chemoresistive gas sensor for trimethylamine (TMA). The morphological and structural characterization of surfaced adsorbed polymer nanocomposite was carried out by FT-IR, SEM, UV-Vis and surface profilometry. While, electrical property was carried out by four-point probe measurement. Prepared rGO/PANi nanocomposite has a percolation threshold around 0.40% vol. fraction, with a conductivity of 8.28 S/m (rsd = 3.0%, n=3) and thickness around 38.58 μm (rsd = 7.63%, n=3. The composite sensor exhibited linear range from 45 to 230 mg/L (r2= 0.9962) and the calculated limit of detection was 25.30 mg/L. It exhibited a repeatable response to TMA gas.

A graphene/nylon-6 nanocomposite was fabricated by incorporating reduced graphene oxide onto a nylon-6 (N6) membrane via vacuum assisted self-assembly (VASA) method. The graphene oxide was synthesised through acid dissolution according to the method of Marcano & Tour and subsequently reduced to graphene using L-ascorbic acid. The surface morphology and electrical characteristic of graphene and its nanocomposites was characterized. The percolation threshold of the prepared nanocomposites was around 1.92% (w/w) with a sheet resistance of 3.839 x 103 Ω per square (rsd= 0.22%, n=4). Different weight ratios of the nanocomposite were tested for its sensitivity towards the amine vapour. The final sensor for trimethylamine concentration has a working concentration range between 23 and 230 mg/L. The sensor exhibited linearity between 45 to 230 mg/L (r2= 0.9917) while the detection and quantitation limit was calculated at 0.39 mg/L and 1.30 mg/L, respectively. This nanocomposite demonstrates that it can be used as a chemiresistor gas sensor that is sensitive and selective to trimethylamine vapour.