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A "water shell" model for the dielectric properties of hydrated silica-filled epoxy nano-composites

Fothergill, J., Zou, C. & Rowe, S. W. (2007). A "water shell" model for the dielectric properties of hydrated silica-filled epoxy nano-composites. Paper presented at the 2007 International Conference on Solid Dielectrics, Winchester, UK.


The electrical properties of epoxy resin have been studied as a function of hydration. The epoxy was studied in an un-filled state, filled with 40 µm SiO2 particles, and filled with 50 nm SiO2 particles. The relative humidity was controlled by saturated salt solutions at ambient temperatures from 298-353 K. Measurements were made using dielectric spectroscopy over the frequency range 10-3-105 Hz. The hydration isotherm (i.e. the mass uptake of water) was established by measuring the mass as a function of relative humidity (RH). It was found that the nanocomposites absorb up to 60% more water than the unfilled and micro-filled epoxies. Dielectric spectroscopy shows different conduction and quasi-DC behaviours at very low frequencies (<10-2 Hz) with activation energies dependent on the hydration and temperature. These observations have led to the development of a “water shell” model to explain this phenomenon.

Publication Type: Conference or Workshop Item (Paper)
Additional Information: © 2007 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Departments: Presidents's Portfolio
School of Science & Technology > Engineering
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