Dielectric spectroscopy of a quenched colloid

Faculty Advisor

Iannacchione, Germano S.


The effects of an external electrical field on a silica-liquid-crystal colloid dispersion are examined as a function of density. These effects have yet to be seen elsewhere and the results from this experiment will lead to a greater understanding of the effect of impurities in a liquid crystal. This experiment is done by varying the frequency and amplitude of the alternating external electrical field and measuring the dielectric constant. Through a comparison of the impure system to the pure system, effects of the impurity can be revealed. Performing these experiments at various densities, the effect of the impurity's concentration can be seen as a critical density. From the rapid change in the dielectric constant the strength of the van-der-Waals forces interacting in the liquid crystal-silica colloid will be revealed. Future work will be done in this field to analyze the interactions more completely and to observe the effects of different dielectrics (liquid crystal), impurities, and changes in temperature of the sample.


Worcester Polytechnic Institute

Date Accepted

January 2006



Project Type

Major Qualifying Project


Restricted-WPI community only

Advisor Department


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