Deep Impact of the Template on Molecular Weight, Structure, and Oxidation State of the Formed Polyaniline

Abstract

In this work we find that polyaniline (PANI), synthesized by aniline chemical polymerization at a surface of template polycarbonate (PC) particles, is significantly different in molecular weight, structural order, oxidation state, and conductivity from a neat PANI. Molecular weight of the PANI phase in the composite (Mw = 158,000) is 1.6 times higher than that of the neat PANI synthesized in the absence of the template particles. Moreover, XRD analysis shows that crystallinity of the PANI phase in the composite is three times higher than that of the neat PANI. Raman spectroscopy indicates that the oxidation level of PANI in the PC/PANI composite is lower than that of the neat PANI. These noticeable changes of the PANI phase properties suggest specific interactions of reagents in the polymerization medium and formed PANI with the template phase as well as an orientation effect of the latter surface. FTIR spectroscopy reveals that hydrogen bonding in the neat doped PANI is weaker than one between -NH- of PANI and C═O of PC at their interface. The discovered differences are supported by the fact that conductivity of the PANI phase in the composite is more than three times higher than that of the neat PANI.

On the importance of interface interactions in core-shell nanocomposites of intrinsically conducting polymers

“…the average crystallite size was 3 times higher than that in the composite (Fig. 6a) [25]. Moreover, in the case of nanocomposites of carbon nanotubes with polyaniline ( Fig.…”

“…Structure differences between the conducting polymer in pure and composite states were confirmed for different (nano)composites [16,17,19,23,25,26,29,[30][31][32][33]. For example, from the XRD-spectra of doped polyaniline and its nanostructured composite with polycarbonate (PC), we found that its degree of crystallinity in the pure state was about 3 times lower, and 6.…”

“…For example, from the XRD-spectra of doped polyaniline and its nanostructured composite with polycarbonate (PC), we found that its degree of crystallinity in the pure state was about 3 times lower, and 6. XRD evidences of the structure differences between the conducting polymers in pure and composite states (core-shell composites): a) the degree of crystallinity and size of crystallites of the doped PANI in pure state and in the shells on the surface of the PC particles (adapted from [25]); the crystallinity changes in doped PANI (b) or PPy (c) phases in nanocomposites with MWCNT (adapted from [29,35]). the average crystallite size was 3 times higher than that in the composite (Fig.…”

Influence of reaction time on the structure of polyaniline synthesized on a pre-pilot scale

“…The assignment of frequencies for Raman spectroscopy varies greatly with the laser frequency used, as well as with the polymer form (base or salt). The bands that are ascribed to the C-H bending in quinoid and benzenoid rings are close to 1160 and 1881 cm -1 , respectively, giving direct information about the degree of oxidation of PAni (Ogurtsov et al, 2013). In the spectra obtained for different reaction times, the band found at 1216 -1223 cm -1 was assigned to the benzenoid ring due to the intensity and because there is not another band in this region that could be assigned to that.…”

“…Intrinsic conducting polymers (ICPs) are among the most successful and important discoveries in modern polymer chemistry and physics. These polymers are successfully used in new advanced materials for photovoltaic, optoelectronics, sensors, antistatic protection, catalysis, corrosion protection and so forth (Ogurtsov et al, 2013). Polyaniline (PAni) is an environmentally stable and tech-nologically important conductive polymer, whose electronic conductivity can be altered reversibly by both oxidation/reduction and acid/base chemistries (Kolla et al, 2005).…”