Reversing-Pulse Electric Birefringence of Poly(γ-benzyl L-glutamate) IV. Electric, Optical, and Hydrodynamic Properties in Helix-Forming Solvents as Evaluated from Field-On and Field-Off Processes

Yamaoka, Kiwamu; Yamamoto, Shinobu; Kosako, Isao

doi:10.1295/polymj.19.951

Cited by 8 publications

(7 citation statements)

References 28 publications

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“…To understand the electrooptical phenomena of the surface on disklike colloidal particles in aqueous media, studies on model materials are important. The electrooptical methods are useful to clarify the electric, optical, and hydrodynamic properties of such particles. − For example, electric birefringence, electric dichroism, and electric light scattering are well-known. In these methods, an electric field is applied to a sample solution for alignment of dispersed particles to the direction of field mostly in a single rectangular pulse.…”

Section: Introductionmentioning

confidence: 99%

Reversing-Pulse Electric Birefringence of Montmorillonite Particles Suspended in Aqueous Media. Instrumentation and the Effect of Particle Concentration, Ionic Strength, and Valence of Electrolyte on Field Orientation

Sasai¹,

Ikuta²,

Yamaoka³

1996

J. Phys. Chem.

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To clarify the electrooptical property of clay particle suspended in aqueous media with a reversing-pulse electric birefringence (RPEB) method, the new RPEB transient theories and orientation function were derived, and the reversing pulse generator, which is also applicable to large particle such as clay , was newly constructed. The transient RPEB theory was derived on the basis of the interaction of applied electric pulse with two electric dipole moments of the macroion : one is due to the ion-atmosphere polarizability a with a single relaxation timle f r for the distortion of ion-atmosphere along the longitudinal axis and the other is due to the intrinsic molecular (instantaneously field-induced) polarizability anisotropy Ll a ' (= a 3-a ll) between the longitudinal (3) and transverse (l) axes of the macroion. The new ori entation function was derived for disklike model. It was assumed that the disklike particle possessed the following three electric dipole moments : (1) permanent dipole moment, (2) saturable induced dipole moment, which is induced in a finite time and saturated at an electric fielld strength and (3) unsaturable induced dipole moment, which is instantaneously induced dipole moment by an external electric field. In the newl y constructed reversing pulse generator a field-effect transistor (MOS-FET) was used instead of a vacuum tube as the switching element. This pulse generator has the following characteristics : (I) a stable output voltage in the 5-300Y range, (2) a widely variable output pulse duration in the 10 I1S-1 .2 s range and (3) a very short time constant of electric pulse (in most cases, 150 ns for buildup and reverse and 50 ns for decay). Moreover this generator could deliver a single rectangular pulse and/or a reversing pulse to high-ionic strength samples, e.g ., 0.2 moldm-NaCI or MgCl~, because of a high electric current resistance of MOS-FET. The theories and reversing pulse generator newly developed were applied to study the effects of particle concentration the ionic strength, and valence of electrolyte on the electrooptical and hydrodynamic properties IOf montmorillonite particles suspended in aqueous media. It was clear that both these theories and generator were very useful for the study of clay particle suspended in aqueous media. RPEB data of Na-montmorillonite particle indicated that the particle possesses no pemlanent dipole moment, but an ionic polarization makes a large contribution to the field orientation. Since the contribution of the ionic polarization increased with an increase of ionic strength, the distortion of sodium ions trapped on the cation-exchangeable sites may be responsible for this ionic polarization. The Na-montmorillonite particles form aggregates of card-house structure, which is an irregular structure, at increased concentrations of added sodium ions, since the optical anisotropy decreases and the diameter of particle increases with increasing ionic strength of added sodium ions. In contrast to the Na-montmorillonite particle, the RPEB

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Section: Introductionmentioning

confidence: 99%

Reversing-Pulse Electric Birefringence of Montmorillonite Particles Suspended in Aqueous Media. Instrumentation and the Effect of Particle Concentration, Ionic Strength, and Valence of Electrolyte on Field Orientation

Sasai¹,

Ikuta²,

Yamaoka³

1996

J. Phys. Chem.

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“…Both AR/A0 and AB/A0 seem to yield Q values lower than they should, on the basis of <f3 2 )w/2(y)w values which were found to be much larger in a previous study. 15 Probably except for cyclohexanone, AR/ A 8 values exceed the theoretical limit of 1.5 at infinitely large Q, which corresponds to the pure permanent dipole orientation ( (r)w = <f3 2 )wf2<Y)w = oo ).…”

Section: Areas As Electric and Hydrodynamic Parametersmentioning

confidence: 94%

“…15 The measurement of signals was carried out at 535 nm and at 20°C. The instrumental time constant was ca.…”

Section: Materials and Measurementsmentioning

confidence: 99%

“…The apparatus, procedure for measurement, and analysis of the experimental data are given_ elsewhere. 15 The contribution of the solvent birefringence to the observed signal was subtracted. The concentration of [Glu(OBzl)Jn was expressed with the residue concentration in mM ( = 1 o-3 mol dm -3 ).…”

Section: Materials and Measurementsmentioning

confidence: 99%

“…In a previous paper of this series, 15 the RPEB study of the electrooptical and hydrodynamic properties of poly(y-benzyl L-glutamate ), [Glu(OBzl)]"' was reported with a particular emphasis on the field-strength dependence of the field-on (the reverse) and field-off (the decay) processes. The present work is an extension of the previous study to the transient RPEB behavior of a fractionated and slightly polydisperse [Glu(OBzl)J. sample in the helix-forming solvents at the low-filed (i.e., the Kerr-law) region, in order to detect the possible field effect on polymer structures.…”

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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

Yamaoka

Yamamoto

Kimura

et al. 1991

Polym J

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ABSTRACT:Reversing-pulse electric birefringence (RPEB) of poly(y-benzyl L-glutamate), [Glu(OBzl)]., with a weight-average molecular weight of 1.71 x 10 5 was measured at 20°C and at 535 nm in helix-forming organic solvents in the low field strength region (0---5 kV cm -1 ), with an emphasis on the transient signal. The theoretical formalism was given for detecting the effect of an applied electric pulse field on reversible change in the electric and hydrodynamic properties of [Glu(OBzl)]" from the normalized signal profiles, areas, and initial slopes of an RPEB signal. A standard experimental procedure was given for unraveling the field-induced change of the electric and hydrodynamic parameters, by utilizing the areas of buildup (Ae), reverse (AR), and decay (AD) processes at the limiting low field. The area ratio, Ae/[(l/2)AR +ADJ= 1, should hold regardless of the degree of polydispersity of a sample, if no direct field effect on polymer conformation is present. The ratio was found to be 0.95 in cyclohexanone, 0.93 in 2~chloroethanol, 0.81 in pyridine, and 0.74---0.81 in chloroform, all being less than unity. Thus, the electric moments and/or the chain length of the [Glu(OBzl)Jn helix were verified to change reversibly to varying extent during the electric field orientation. KEY WORDSReversing-Pulse Electric Birefringence / Poly(y-benzyl Lglutamate) / Field Effect/ Electro-Hydrodynamic Property/ Area Method/ With the aim of perfecting the reversingpulse electric birefringence (RPEB) method and applying it to macromolecules in solution to elucidate the electric, optical and hydrodynamic properties, the RPEB study has been carried out in our laboratory on many biopolymers and related polyelectrolytes. 1 -16 A major problem associated with these systems is polydispersity regarding the molecular weight and chain length. This problem is almost always encountered with natural macromolecules of biological interest, which are prepared by extraction from living organisms, and also with the synthetic polymers, which are prepared by in vitro polymerization. Thus, the polydispersity effect must be taken into account for quantitative analysis of the electric birefringence signal. 1 7 Yoshioka and his coworkers were the first who seriously considered this effect in the analysis of the single square-wave pulse electric birefringence (SPEB) data of poly(o:-L-glutamic acid). 18 -21 The RPEB method is usually superior to the conventional SPEB method in that the transient signal at low fields can yield sufficient infonnation on the polydispersity effect and the electric and hydrodynamic properties of the rodlike or helical polymers. 1 7 * To whom correspondence should be addressed. Another major problem associated with an orienting electric pulse field is the direct field effect on the polymer conformation, which may change concurrently with molecular orientation. This field effect has seldom been studied mostly because of the difficulty involved in detecting such field-induced conformational changes for polydisperse samples....

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Investigation of macromolecules exhibiting the structure of a once-broken rod by molecular optics. 1. Synthesis and investigation of poly(γ-benzyl L-glutamate) with short joints

Ul’yanova¹,

Baranovskaya²,

Liubina³

et al. 1991

Macromolecules

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Reversing-Pulse Electric Birefringence of Poly(γ-benzyl L-glutamate) IV. Electric, Optical, and Hydrodynamic Properties in Helix-Forming Solvents as Evaluated from Field-On and Field-Off Processes

Cited by 8 publications

References 28 publications

Reversing-Pulse Electric Birefringence of Montmorillonite Particles Suspended in Aqueous Media. Instrumentation and the Effect of Particle Concentration, Ionic Strength, and Valence of Electrolyte on Field Orientation

Reversing-Pulse Electric Birefringence of Montmorillonite Particles Suspended in Aqueous Media. Instrumentation and the Effect of Particle Concentration, Ionic Strength, and Valence of Electrolyte on Field Orientation

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

Investigation of macromolecules exhibiting the structure of a once-broken rod by molecular optics. 1. Synthesis and investigation of poly(γ-benzyl L-glutamate) with short joints

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