Interpretation of electrical polarization and depolarization mechanisms of bioactive glasses in relation to ionic migration

TSDC spectroscopy of relaxational and interfacial phenomena

“…The depolarisation of BG consisted of three processes that depended on the neighbouring coordinations of travelling sodium ions during polarisation. The ion mobility contributing to the polarisation process showed a dependence on the polarisation temperature, which produced large electrical charges at the higher polarisation temperature [200]. Because the polarisation mechanism governed the depolarisation, ionic migration ( Fig.…”

“…Obata et al [200] studied electrical polarisation and depolarisation processes of 45S5 type bioactive glass (BG) by TSDC and complex impedance measurements. The depolarisation processes were found to consist of three processes, observed as three peaks, P1, P2 and P3, in the TSDC spectra (Fig.…”

Chemico-Vector and Mechanochemico-Vector Properties of Polarized Glass-Ceramic Silicophosphate of Narpsio

“…Although the phenomena corresponded to the second peak at 350c C was not yet completely analyzed, the peak was attributable to structural changes andor relaxations caused by thermal stimulation. The stored charge was recognized to be huge, compared to the polarized hydroxyapatite ceramics 16 and bioactive glasses, 17 and was attributed to the high electrical conductivity of gc: Narpsio. Taking into account of mobile Na ࢪ ions in Na 5 YSiO 4 -type Narpsio structure, the ratio of Na ࢪ ions taking part in polarization can be estimated as 100 ppm to 0.1ಚ of all Na ࢪ ions, including immobile ones, in the structure.…”

Suppression effects of dental glass-ceramics with polarization-induced highly dense surface charges against bacterial adhesion

“…The TSDC spectra of polarized dental glass-ceramics showed several peaks characteristic of charge carriers. In an earlier study, we successfully controlled alkali ions in 45S5-type bioactive glass through the electrical polarization process 16) . The glass phase of dental glassceramics contains alkali oxides, such as sodium and potassium oxide, which can move through the network of the glass matrix 23) .…”

“…In accordance with the electrical polarization process reported in previous studies 13,16) , the specimens were electrically polarized in a DC field of 0.1 or 1.0 kV/cm in air at 250°C for 1 h. The ceramic surfaces placed in contact with the anode and the cathode were defined as the N-surface and the P-surface, respectively. The control group was prepared using the same equipment by heating without applying the DC voltage (herein, it is termed the H-surface) (Fig.…”