No abstract

Composite of reduced graphene oxide (rGO) and polyaniline (PANI) have gained much attention in industrial applications especially for the fabrication of supercapacitor and flexible sensors. Nevertheless, existing studies mainly focus on the application efficiency and are lacking information on how morphology of the nanoparticles can affect the electrode properties.Herein, the effects of shape of PANI on the electrode resistivity were systematically investigated. PANI of different shapes was synthesized using different reagents, namely H 2 SO 4 , CH 3 COOH, H 2 O, and NH 3 ÁH 2 O, which induced formation of globule, tube, plate, and flake-like PANI. rGO-PANI composite was then produced using ex situ method and cast on a PVC substrate to form a flexible electrode. The rGO-PANI globules displayed superior electrical conductivity owing to its high protonation level. The resistivity of this sample was found to be 0.015 ± 0.002 Ωcm, which is lowest as compared to the counterparts. Interestingly, electrode made of rGO-PANI plates had a slightly lower electrical resistivity than rGO-PANI tubes despite its low protonation level. It is speculate that the aspect ratio characteristic of the PANI might have influence the electron mobility. rGO-PANI electrode was found to exhibit a lower specific resistivity than pure rGO and pure PANI, evincing the presence of synergism.

By virtue of the rapid development of technologies in the era of Industrial Revolution 4.0, additive manufacturing technology enables faster production, diverse raw materials, infinite shapes and geometries for fine products as compared to traditional manufacturing methods. Among many manufacturing materials, nanomaterials have attracted extensive attention due to their wide variety, high strength, and effect of catalytic, quantum, surface and boundary. From the aspect of an industrial manufacturing process, the practical advantages of using additive manufacturing techniques to fabricate nanomaterial-incorporated membranes for gas separation are valuable. This paper reviews the potential of using additive manufacturing in the fabrication of membranes incorporated with nanomaterials for gas separation.

Flexible gas sensors made of polyaniline (PANI)‐reduced graphene oxide (rGO) nanocomposite were prepared using three different substrates, namely filter paper, cotton fabric, and weighing paper, through in‐situ reduction of GO and in‐situ polymerization of aniline. Preliminary analysis showed that the PANI/rGO coated on filter paper possesses a superior electrical conductance than PANI/rGO coated on cotton fabric and weighing paper. Such observation was attributed to the good attachment of the PANI/rGO nanocomposites onto the high‐density mesh‐like structure of the filter paper with rough surfaces. In contrast, PANI/rGO coated onto weighing paper and cotton fabric of different surface structures presented lower‐to‐almost negligible conductance. Accordingly, PANI/rGO filter paper was selected for the subsequent evaluation of gas sensing properties. The gas‐sensing performances of the PANI/rGO filter paper sensors indicated that the 5 wt% PANI/rGO (i.e., 5 wt% rGO) sample exhibited the best response of 306% for 500 ppm carbon dioxide (CO2) gas at room temperature with a recovery rate of 41.5%. On the other hand, the optimum recovery rate of 59.5% was identified at 0.5 wt% PANI/rGO sample which exhibited a response of 155%. Owing to the synergy effect, the PANI/rGO sensor outperformed the sensor made of pure PANI or pure rGO.