Low temperature thermal windowing (TW) thermally stimulated depolarization current (TSDC) setup

Abstract

We report here the design and implementation of a precise and easy to operate thermally stimulated depolarization current (TSDC) measurement setup for temperature range 77–400 K. The sample loading is made simple by sandwiching the sample between two copper disk electrodes using a spring-shaft arrangement. The salient features of the setup are precise thermal windowing (TW) capability and linear heating rate over the entire temperature range. The resolution in the measurement of depolarization current is of the order of 7×10−14 A. This is achieved by means of good electrical insulation of the electrodes from the rest of the setup and utilization of low noise circuitry. Precision of the system is demonstrated by its capability to resolve constituent relaxations present in complex relaxation processes using the TW experiments. Study and detection of glass transition processes in polyethylene terephthalate, four relaxation processes in polymethyl methacrylate, glass and crystallization transitions along with the onset of ferroelectric Curie transitions in polyvinylidene fluoride and characterization of electret state in amino acids l-arginine, phenylalanine, tyrosine, tryptophan, glutamic acid, glutamine and methionine show the versatility of our setup.

Low temperature dielectric relaxation of poly (L-lactic acid) (PLLA) by Thermally Stimulated Depolarization Current

“…Solvent cast PLLA film of 15 mm diameter and 0.11 mm thickness is used as a sandwich between metallic copper electrodes for TSDC measurements using a homemade but versatile setup [4]. The PLLA film has been poled at temperature, T P =350K.…”