Pulsed Electric Linear Dichroism of Triphenylmethane Dyes Adsorbed on Montmorillonite K10 in Aqueous Media

Electrooptics of β-FeOOH Particles in Aqueous Media

“…Then, the terms containing parameters p and q in Eqs. [1] and [2] become mathematically undistinguishable (23), though physically they are either of classical ( p) or of ionic (q) origin. Hence, the slowly fluctuating ionic dipole moment (τ * 1) has often been termed the permanent-like dipole moment (19,20,22,23) or the surface permanent dipole moment (17).…”

“…It should be emphasized that the quantitative analysis of a single RPEB signal, once measured under appropriate conditions, with the aid of theoretical expressions (Eqs. [1]- [3]) can yield easily and conveniently vital information on the field orientation of colloidal particles dispersed in ionic aqueous media.…”

“…[1]- [3]. The procedure for signal fitting is first to evaluate the rotational relaxation time τ θ from the field-off decay curve by the area method, as shown in a previous paper (28).…”

“…The electrooptic methods (7), such as electric dichroism (ED) (1,8), electric birefringence (EB) (2)(3)(4)(5)8), and electric light scattering (ELS) (7,9), were extensively applied for such investigations. The electrooptic quantities are quite important from the fundamental and practical points of view because they are directly related to the stability of the dispersed colloidal systems at low and high concentrations.…”

Adsorption Study of Cationic Dyes Having a Trimethylammonium Anchor Group on Hectorite Using Electrooptic and Spectroscopic Methods

“…Dye adsorption was also applied to characterize clay mineral surfaces (10) and Rytwo et al used methylene blue and crystal violet for determination of exchangeable cations in montmorillonite (11). Recently Yamaoka and Sasai (12) presented pulsed electric linear dichroism (ELD) as a useful method to obtain additional information about the orientation of the adsorbed dyes. In a detailed theoretical analysis they calculated roll, tilt, and inclination of the dye molecule at the clay mineral surface.…”