Broadband dielectric spectroscopy from sub-GHz to THz frequency region on hydrated bentonite

• Main Authors: Lozada, Lou Serafin M., Tapia, Alvin Karlo G., Gillado, Armida V., Yamamoto, Naoki, Tominaga, Keisuke
• Other Authors: Asian Spectroscopy Conference 2020
• Format: Conference or Workshop Item
• Language: English
• Published: 2020
• Subjects: Science::Chemistry; Broadband Dielectric Spectra; Sodium Bentonite
• Online Access: https://hdl.handle.net/10356/144348
• Institution: Nanyang Technological University

Understanding how water molecules interact with one another and with clay under a confined geometry at different temperatures are key information in energy storage applications and nuclear waste disposal. Here we present an investigation of the dielectric response from 100 MHz to 1.8 THz of sodium bentonite at different hydration levels from 233 K to 293 K. Figure 1 shows the complex dielectric spectra of hydrated bentonite. Our previous studies have shown that for hydrated soft matters such as protein [1] and lipid bilayers [2] the dielectric response in the frequency region from sub-GHz to THz are due to the relaxation processes and vibrational processes, which are modeled using a Cole-Cole function and Lorentzian function, respectively, as shown below. The first term is the ion conductivity term, which may be important for conducting materials.