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The electrochemical polymerization of polyaniline (PANI) was studied using correlative measurements of electrochemistry and UV–vis spectroscopy, i.e., spectroelectrochemistry. The electropolymerization of PANI was performed in an acidic medium (1 M HCl) containing 0.1 M aniline with cyclic voltammetry (CV) in a potential window from −0.3 to 1 V and a 50 mV s−1 scan rate. At the same time, UV–vis absorbance spectra in the wavelength range from 200 to 900 nm were measured for every 10 mV change in the CV. The CV results show the oxidation of the monomer at a high positive potential (0.9 V vs Ag), the continuous growth of the PANI film and the transformation between the three best-known forms of PANI redox in the potential range between −0.3 V and 1 V. In parallel, the spectroscopic study confirmed the formation of PANI oxidation. The spectroscopic results showed the formation of the final conductive PANI product (emeraldine salt) due to the absorbance of the formed charge carriers (polarons, bipolarons) during the polymerization. The correlative electrochemical/spectroscopy study gave an additional dimension to the PANI polymerization mechanism, where not only was the oxidation the lead type of reaction, but the reduction was also found to play an important role.

A holistically described radical-induced redox chemistry modelling allows for a direct assessment of the in situ experiments inside a liquid-cell TEM.

In the present work, multiphase polycrystalline BTO nanorods were synthesized using template‐assisted sol–gel deposition and their structural evolution was studied using thermo Raman spectroscopy, X‐ray diffractometry and high‐resolution transmission electron microscopy (HRTEM). In the BTO nanorods, the tetragonal phase was the dominant one, while both Raman and HRTEM indicated a coexistence with the high‐temperature hexagonal polymorph. This phase was stable across the whole of the investigated temperature range (from −95 °C to 200 °C). The investigated nanorods underwent a diffuse phase transition from tetragonal to cubic with respect to the temperature, whereas the final phase‐transition temperature was shifted to higher values compared to that expected for BTO. The low‐temperature orthorhombic‐to‐rhombohedral phase transition was also shifted to higher temperatures. These differences could be explained by the strain induced by the presence of hexagonal nanolamellas intergrown within the tetragonal nanocrystals. This result indicates that the temperature of the ferroelectric phase transition in polycrystalline BTO nanorods can be manipulated by introducing a stable hexagonal phase. Copyright © 2012 John Wiley & Sons, Ltd.