Reactive doping of PAni–CSA and its use in microwave absorbing materials

Abstract

Conductive coatings have been studied for static dissipation and as microwave absorbing materials. The doping process of polyaniline (PAni), which makes it conductive, is an important stage that determines the coating performance. For this purpose, polyaniline was doped by reactive processing in a torque rheometer using different molar ratios between PAni and acid (PAni:CSA) at three different temperatures (80, 90, and 100-C). Aqueous solution doping was also used in the ratio of 1:2 of PAni/CSA, with the aim to investigate the influence of different methods of PAni doping on its characteristics and, consequently, on the performance of coatings. Thermal analyses of the processed materials showed that PAni doped by both routes, reactive and solution processing, showed similar behaviors. X-ray diffraction analyses showed a semicrystalline structure for the PAni-CSA doped by reactive processing using high CSA concentrations and temperature. It was also observed that the doping process affects the dispersion of the components into the conductive coatings. Microwave absorption measurements (8-12 GHz) of PU-doped PAni blends showed the dependence of the doping type, the PAni-CSA concentration, and the mixing conditions of the components on the coating performance; it was found up to 99% of attenuation of the incident radiation for some composites in a narrow frequency range. The microwave absorption efficiency of the coating samples prepared by using the reactive doping process indicates the advantage of this methodology over solution doping. Moreover, the reactive process addresses the environmental requirements.

Tuning the work function of polyaniline via camphorsulfonic acid: an X-ray photoelectron spectroscopy investigation

“…A 100 nm thick layer of silver was vacuum-evaporated on part of the surface for each film using a shadow mask. 37 All four polymers were observed to have a threestage mass loss as is illustrated in the derivative curves shown in the inset of Figure 4 (a). The Hall Effect measurements were performed on PANI:CSA films using an Ecopia HMS-5000 Hall Effect system at room temperature.…”

Conducting Polymeric Composites Based on Intrinsically Conducting Polymers as Electromagnetic Interference Shielding/Microwave Absorbing Materials—A Review

“…The microwave absorbing properties were also evaluated for systems involving poly(ethylene-co-propylene-co-5-methylene-2-norbornene (EPDM), poly(styrene-co--butadiene) (SBR) and polyurethane (PU)loaded with PAni [119][120][121]. For these studies, the doping process of PAni in the non-conductive form (EB) was performed during the melt mixing of polymer matrix and the protonating agent.…”

Conducting Polyaniline-Electrical Charge Transportation

“…On the other hand, the organic acid that confers certain solubility and high conductivity on PANI is 10-camphor sulphonic acid (CSA) [12] where doped in polyaniline presents a high conductivity (>1  10 2 S·cm −1 ) in the presence of m-cresol solvent. It provides high conductivity and crystallinity values to the PANI-CSA complex system, conferring on the polymer a metallic like-behavior [13]. In the recent years, HCl and CSA doped PANI have been used in Poly (methylmethacrylate) PMMA composites to produce highly conductive electrospun nanofibers by our group previously [14][15][16], in which the investigation devoted to microwave hall mobility and electrical properties.…”