Influence of Dispersed Nanoparticles on the Kinetics of Formation and Molecular Mass of Polyaniline

Abstract

Using a combination of the open circuit potential and pH profiles of aniline (An) polymerization and their mathematical treatment, we develop a new convenient semiquantitative approach to determine the influence of the dispersed nanoparticles (e.g., TiO nanoparticles) on the kinetic features of this process and molecular mass of the formed polyaniline (PANI). It is revealed that the reciprocal values of the polymerization stages, namely, the duration of the induction period, of homogeneous and heterogeneous pernigraniline (PN) accumulation, and of PN reduction with An, are linear functions of the weight fraction of the nanoparticles. We found that when nanoparticles are added the weight-averaged molecular weight of PANI initially increases from 56 000 to 79 000 and the polydispersity index drops from 3.9 to 1.7. However, at high TiO concentrations, the former dramatically decreases, whereas the latter increases. We use the relative proton concentration as a function of time and the different extents of acceleration of the consecutive stages of An polymerization to explain the changes in the molecular weight distribution of PANI with different contents of TiO nanoparticles in the polymerization medium.

Effect of Cobalt Phthalocyanine on the Chemical Polymerization of Aniline

“…The inverse values of the characteristic points on the OCP and pH profiles are linear functions of the additive concentration . In the example being studied, a linear dependence on the CoPc concentration was also demonstrated (Figure ).…”

“…The semi‐quantitative approach developed by Ogurtsov et al. for the analysis of individual polymerization stages takes into account the characteristic points and the general appearance of OCP profiles that depend on the amount of the substrate added . It should be noted that the type of OCP profiles obtained in aniline polymerization at various CoPc concentrations contains the basic points for classical polymerization (Figure b), which indicates that the reaction occurs by a similar mechanism.…”

“…According to literature data, a number of successive stages can be distinguished on the OCP plot: induction period ( t i ); accumulation of insoluble pernigraniline (PN) ( t 1 ); acceleration of the reaction and complete APS consumption ( t max ); formation of an emeraldine salt upon PN reduction ( t e ) . It was previously found that upon reaching the time t i , the formation of an aniline dimer (p‐semidine) is observed, indicating that the initiation stage is over …”

“…There are numerous examples in the literature concerning the use of various methods for studying the oxidative polymerization of aniline, for example, colorimetry, UV, NMR spectroscopy, GLC, pH measurement, etc. However, the measurement of open circuit potential (OCP) is believed to be one of the most important and simplest techniques for monitoring the process . This method allows one to obtain information about the redox state of the polymer formed.…”

H2S Sensing Material Based on Cotton Fabrics Modified with Polyaniline

“…[36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] PAni's electrical and optical properties are dependent on the different oxidations states of this conducting polymer. [32,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] These oxidation states are leucoemeraldine, protoemeraldine, emeraldine, nigraniline and pernigraniline. However, the three most studied oxidation states are leucoemeraldine (y ¼ 0completely reduced state), emeraldine (y ¼ 0.5) and pernigraniline (y ¼ 1fully oxidized state).…”