Transient SANS Studies on p‐Tetrafluorethylen (p‐TFE)

Abstract

Dlfyusion : Neutron Scattering / Nonequilibriutn Phenomena I Solutions Time dependent anisotropic small-angle neutron scattering (SANS) patterns of p-TFE fibrilles are presented. In the experiment the fibrilles were exposed to a parallel AC-electric field in which the on and off cycle time had been adjusted to the orientation time of the fibrilles. The time resolution of the experiment was 40 ms. By an analysis of the time evolution of the SANS pattern relaxation times for alignment T, and randomisation T: were deduced. Both times, being equal within the error bars, are around 150 ns. The scattering curve for the fibrilles could only be fitted with the assumption of considerable polydispersity of their diameter.

Electric birefringence anomaly of solutions of ionically charged anisometric particles

“…As the other discussed systems, the p-TFE fibres can be aligned in electric DC-and AC-fields [31]. In the anomaly region the birefringence signals change sign for increasing AC-frequencies, a typical behaviour of all the discussed systems, and as shown in Fig.…”

“…At a later time it became clear that the results from one type of measurements (AC or DC) can be calculated from the other types of measurements [2]. The result that the solutions with a crossover of sign of the birefringence when measured with AC-fields became important at a later time when in addition to birefringence measurements, SANS measurements were made on the same solution [20,31].…”