Cyclic temperature dependence of electrical conductivity in polyanilines as a function of the dopant and synthesis method

Abstract

Most of the studies dealing with polyanilines (PANIs) are focused on electrochemical polymerization; however, chemical polymerization is more suitable for large-scale production. In order to develop commercially viable, clean, effective materials for thermal sensor devices, temperature dependent electrical response has been studied in PANIs obtained by simple, low-cost synthesis conditions, transferable to industrial processing. PANIs doped with HCl, dodecylbenzene sulfonic acid (DBSA) and sodio-5sulfoisophtalic acid (NaSIPA) were prepared by chemical oxidative polymerization, through direct and indirect routes of synthesis. TEM images disclosed formation of nanorods and microfibrils. Microstructural analysis confirmed differences in doping level and crystallinity which were related with the PANI conductivity. Two PANI-DBSA synthesized by direct and indirect methods, exhibit the best conductivity retention up to 150 ºC. In cyclic tests, they show excellent performance after 4 heating-cooling cycles up to 70 ºC. The amplitude of electrical response for 2 PANI-DBSA obtained by direct synthesis is twice the value of PANI-DBSA prepared by indirect route. Conversely, the latter displays slightly better repeatability due to its lower moisture content. This study suggests that both PANI-DBSA are suitable for use in electronic applications, under ambient conditions below 150 ºC, and are promising materials for temperature sensor applications.

Multifunctional electromechanical and thermoelectric polyaniline–poly(vinyl acetate) latex composites for wearable devices

“…In P30L70 dispersions (Fi. 2B-C), PANI-HCl exhibits the same nanorod morphology described in a previous work [30]. Nanorods with 10-15 nm diameter and variable length from70 to 300 nm, are highly aggregated forming small clusters of thickness ranging from 65 to 95 nm.…”

“…Conductive networks within a composite film also dominate the resistance-temperature properties, which is dominated by thermally activated charge carriers [1]. The literature reports similar thermal properties for PANI-DBSA samples [30].…”

“…Additionally, the upshifts of several PANI bands (δNH + , Q, B), which are indicative of the protonation level [34], suggest a partial deprotonation of PANI-HCl for PANI contents below 30 wt.% (Fig. S4, Supporting information).…”

Electroconductive materials based on carbon nanofibers and polyaniline

“…The synthesis is based on a modified literature procedure . Briefly, 0.3 g of CNF was dispersed in 20 mL solution containing 3 mol/L ANI and HCl 1 mol/L, then 20 mL solution of 3 mol/L ammonium persulfate in HCl (1 mol/L) was added dropwise under ultrasound irradiation and magnetic stirring.…”

An optical-magnetic Material as a toxic gas filter and sensing device

“…However, the established levels for humans to be exposed without causing damage is below 10 ppm. 53,54 Thermogravimetric studies Fig. 12 shows the TGA of the materials before exposure (a) and aer exposure (b) to H 2 S.…”