En undersøgelse af Maxwell Wagner-modellen: Investigation of the Maxwell Wagner model

Julie Lundbak Kofod, Morten Levinsky Thorsboe, Kristoffer Aage Bredahl & Liv Bjerg Lillevang

Studenteropgave: Semesterprojekt

Abstrakt

The study investigates the Maxwell Wagner model theoretically and experimentally. The model describes the dielectric response of an inhomogeneous material. The purpose is to set up a con- trolled experiment to test the model and its limits. Dielectric spectroscopy is made on different samples in the temperature range from 230 K to 197 K and a frequency range from 10−2 Hz to 106 Hz. Experiments with layered glycerol and teflon is well described by a model that defines the di- electric constant of the layers by connecting two capacitors in series. The measurements are sensitive to glycerol which tends to leak. Corrections are made by including a capacitor in pa- rallel with the layers in the model. Measurements on suspensions with glass spheres in glycerols show discrepancy between the data and the Maxwell Wagner model. The measurements show a large reduction of the relaxation peak amplitude and an unexpected conductivity which is not accounted for in the model. Furthermore an experiment is made on air bubbles in glycerol with an unknown volume fraction. The measurements are well described by the Maxwell Wagner model which is used to estimate the volume fraction of air. Due to the uncertainties with the experiments it is only possible to discuss the limits of the Maxwell Wagner model theoretically.

UddannelserFysik, (Bachelor/kandidatuddannelse) Bachelor el. kandidat
SprogDansk
Udgivelsesdato22 jan. 2016
VejledereKristine Niss

Emneord

  • Glycbob 2000
  • Maxwell Wagner-model
  • Dielectric spectroscopy
  • Inhomogeneous material
  • Two-layered system