Percolation Effect on the Complex Permittivities of Polymer Blends

Hsien Wen Chao^1*, Yun Yu Lai², 張存續¹

¹物理系, 國立清華大學, 新竹, Taiwan
²Department of Polymer Science, University of Akron, Akron, USA

* Presenter:Hsien Wen Chao, email:s9822817@m98.nthu.edu.tw

This study focuses on the measurement and analysis of the complex permittivities of the polymer blends using the field enhancement method (FEM). The blends, consisting of air-powder or solvent-solute mixtures, are placed in a Teflon holder and inserted into the FEM cavity to determine the complex permittivity. The resonant frequency and quality factor of the FEM cavity coupled with the samples provide information on the dielectric constant and loss tangents of the blends. To extract the complex permittivities of three specific samples of DC-840, MCL-805, and MCL-Siloxane, we employ effective medium theories and the high-frequency structure simulator (HFSS), together with the measured data. The results reveal that when the volume fraction of the DC-840 solute in the xylene solvent surpasses a specific threshold, the dielectric constants and the loss tangents experience a notable increase. This phenomenon, known as percolation, strongly correlates with the viscosity of polymer blend. The observed percolation effect on the dielectric behavior is further elucidated using the generalized dielectric constant and the Debye model. By employing these models, the percolation effect and its impact on the dielectric properties of the blends can be explained and clarified.

Keywords: Percolation Effect, Polymer Blends, Enhanced Field Method, Contour Mapping Method, Complex Permittivity