Reversing‐pulse electric birefringence of poly(γ‐benzyl‐L‐glutamate). III. The temperature dependence of the transient and steady‐state behavior in cyclohexanone

Abstract

Higashisenda-machi, N h -k u , Hiroshima 730, Japan synopmaThe reversing-pulee electric bkfringence (WEB) technique was applied to the study of the temperature d e c t on the electrooptical and hydrodynamic properties of a fractionated [Glu(OBzl)], aample, which is molecularly dissolved in cyclohexanone. The aim was to develop a standard analytical method for thermal denaturation and temperaturc+induced confonnational traaeitiona The field-on revand steady-state signal, and the field-off decay signal, were measured at 536 nm and at a constant low field strength (a. 3 kV/m) over a wide temperature range (6-90°C). The steady-state birefringence and the relaxation time in the decay proceas were also measured at two constant temperatures (5 and 70°C) over a wide field strength range (E 5 20 kV/m). By the combination of these two differeat sets of RPEB measurements, the unwanted effect of the high pulee field on polymer confonnation at elevated temperaturea could beminimized . Together with the doneity and vhcogity of cyclohexanone measured between 5 and 96°C. the following quantitiea could be evaluated: the weight-average permanent dipole moment and polarizability anisotrOpy, the reduced optical anisotropy factor (Ag/n), the weight-average length, and the degree of polydispersity. AU t h e quantities, except for Ag/n, were found to be almoet independent of temperature (5-90°C) and concentration (1.54-427 mM).

Electric-Field-Induced Perfect Anti-Nematic Order in Isotropic Aqueous Suspensions of a Natural Beidellite Clay

“…In Table , we compare our results for beidellite clay with the data reported in the literature for various, strongly anisometric, disk-like and rod-like particles in aqueous suspensions. As seen from the table, the specific excess polarizability of the beidellite particles is among the highest reported values, comparable to that of extremely thin charged rods, , a few times larger than that of the TMV, , a classical example of highly polarizable particle of similar volume V p , and up to 2 orders of magnitude larger than the Δ A sp values reported for other plate-like clay particles. , Moreover, the beidellite Δ A sp value is somewhat higher than the values reported for gold rods, , expected to give Δ A sp saturated to the upper limit predicted by the MW model, because of the very high bulk conductivity K p of the particles.…”

Reversing-Pulse Electric Birefringence of Poly(γ-benzyl L-glutamate) V. Field-Induced Changes of Electric and Hydrodynamic Properties in Helix-Forming Solvents as Revealed by Transient Signals

“…Since the field-on steady-state birefringence /).n should be the same in all RPEB processes (cf eq AlO), the ratios of any two of three transient processes are given from eq 6---8 as (12) 6 (14) (/3o…”