Broadband dielectric spectroscopy (BDS) measurements have been carried out on a nanostructured hydrophilic model system to gain insight into the atomistic level mechanism of adsorption-induced dielectric changes. Titanate nanowires (TiONWs) were investigated between 10 mHz and 1 MHz under various humidity conditions. The processes contributing to the measured dielectric response were identified, and their dependence on water surface coverage was discussed in detail. Three relaxation processes and an imperfect ionic conduction were found in the investigated frequency window. Exponential relationships were found between the different dielectric quantities and the amount of adsorbed water. The conductivity variation originates from the exponentially increasing charge carrier concentration, while the relaxations in the middle frequency range have a common, interfacial origin. The high-frequency loss process arises from the orientation relaxation of a real dipolar moiety of the system.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films