Dielectric study on coupling constant of lower critical solution of poly (vinylmethylether) in water

Dielectric relaxation measurements by time domain reflectometry were performed on a lower critical solution of poly (vinylmethylether) in water over a frequency region from 100 kHz to 10 GHz and at temperatures between 5 °C and the phase separation temperature TP. Two relaxation peaks could be observed. One observed around 10 GHz is caused by reorientation of water molecules and the other observed at 10–100 MHz is due to a micro-Brownian motion of polymer chain. Absorption and dispersion curves of the latter process can be fitted well to those calculated by the coupling model. Coupling constant n observed increases with temperature. This is the first finding and gives an evidence of validity of the coupling model.