One of My Undergraduate Projects

The composition of polymeric materials has important implications for their macroscopic properties. Inevitably, the question arises how changes at the molecular level impact macroscopic material properties and how molecular dynamics between a rigid and a flexible component are affected over a range of temperature.

Dielectric relaxation spectroscopy is an extremely effective method for characterizing in detail the molecular dynamics over a large range of time scales. The technique is sensitive to orientational motions of permanent dipoles and to translational contributions of ions. Combining different experimental techniques (network analysis, reflectometry, gain/phase analysis, and time domain modulus relaxation) our accessible range of frequencies covers 20 nHz to 20 GHz, equivalent to time scales between 10⁷ s and 10^-11 s. The usable sample temperatures range from 25 K to 473 K. A typical resolution limit is tan 10^-3 - 10^-4, but tan 10^-7 can be resolved at f = 1 kHz.

Broadband dielectric relaxation spectroscopy was used to study the molecular dynamics of different polymer blends (Ultem 100 and PI527) over a wide temperature range (300-600 K). Numerous experiments provided us with data about the temperature-dependence of alpha-relaxation processes and other relaxation parameters.

Ultimately, the data generated in this project were incorporated into a study carried out by Dr. Bernhard Schartel at the University of Marburg, Germany.