Influence of added hydrogen bonding agents on the chiroptical properties of chiral polyaniline

Green Synthesis of Novel Polyaniline Nanofibers: Application in pH Sensing

“…Chiral polyanilines can be synthesized using chemical oxidation of a chiral agent [13,14,15,16,17,18,19] or by electrochemical polymerization [20,21,22], chemical vapor phase polymerization [23], a non-green approach, or chiral complexation with the chiral palladium complex [24]; the latter method incorporates chiral anions onto the main chain of PANI as counter-ion dopants through electrostatic interaction or hydrogen bonding. Naturally occurring amino acids can act as a dopant, where the -COOH group provides doping to conducting polymers by hydrogen bonding, which in turn stabilizes the chiroptical properties of optically active PANI [25]. PANI with specific morphologies have drawn increased attention because of their different physical and chemical properties, which broaden the application to various fields, such as chemical sensor and biosensors, controlled release and delivery, light-emitting and electronic devices, etc.…”

Chemical Effects of a Solvent-Limited Approach to HCl-Doped Polyaniline Nanopowder Synthesis

“…This band appears only in the CS samples, which represents a significantly strong charge localization which may transition to bipolaron depending on synthesis conditions. , If correct, this band indicates that a polaron transition is favorable in the CS-synthesized PAN relative to the other synthesis approaches. Additionally, this band can be attributed to a compact coil conformation of the segments in doped polyaniline, ,,− which has been shown to lead to lower conductivity. − Most notably, the existence of this band in CS confirms its proposed electronic structure and polymorphism obtained via the RS analysis and interpretation. Specifically, the 850 nm band indicates the significant occurrence of bipolaron electronic structures in CS, whereas bipolaronic lattice vibrations (ES-I) were observed in the Raman spectra of CS as well .…”

“…The higher wavelength band observed at ∼850 nm indicates significant electronic differences between polyaniline samples. This band is likely contingent upon the existence of dicationic, bipolaron electronic transitions in doped polyaniline ,, and/or is caused by localized polaronic species ,,,− with shorter conjugation length . This band appears only in the CS samples, which represents a significantly strong charge localization which may transition to bipolaron depending on synthesis conditions. , If correct, this band indicates that a polaron transition is favorable in the CS-synthesized PAN relative to the other synthesis approaches.…”

Protein-Induced Synthesis of Chiral Conducting Polyaniline Nanospheres

“…As shown in Figure C,D, from which we got to know that chiral PANI was obtained in the presence of Hb or BSA, indicating that protein prominently induce the chirality of PANI. Besides, the dissymmetry g -values (Δε/ε) of chiral PANI induced by Hb and BSA as shown in Table indicated that with the increasing of protein content, the g -value was also improved . This is the first time to report the phenomenon that protein can act as the chiral inducer, which was significantly distinctive compared with previous reports. − …”

“…Besides, the dissymmetry g-values (Δε/ε) of chiral PANI induced by Hb and BSA as shown in Table 1 indicated that with the increasing of protein content, the g-value was also improved. 15 This is the first time to report the phenomenon that protein can act as the chiral inducer, which was significantly distinctive compared with previous reports. 1 −11 Subsequently, the pH-dependent experiment was used to investigate the chirality of PANI conducted by doping and dedoping process.…”