Suspension birefringence

Formula (4.371) proves explicitly that the suspension birefringence is an even function of the applied field amplitude. For this reason, in response to the excitation of the frequency go the optical anisotropy Av oscillates with the basic frequency 2co. The higher-rank harmonics induced by the saturation behavior of Av((0) are the multiples of the basic one. It is also clear that besides the oscillatory contribution, the frequency spectrum of Av contains a constant component. 

Figure 17.10 Reproduction of the first recorded tactoids of cellulose nano-ciystals in suspension. Birefringent bands are visible between crossed polars.

High molecular weight mesophases were first studied during the late 1930 s using suspensions of tobacco mosaic virus (TMV). Bawden and Pirie (26) reported a solution of TMV separated into two phases as the concentration was increased, one of which was birefringent. 

Colloidal dispersions suspensions and aggregates Viscosity and transient electric birefringence study of clay colloidal aggregation. Physical Review E 65, 21407-21500... 

The Optical Theorem Form Dichroism and Birefringence From Dilute Suspensions 71... 

The scattering of light from a suspension of particles will cause the light transmitted through such a material to be changed in phase and amplitude. If particles are nonspheri-cal, and have a net orientation, a birefringence and dichroism will result. 

For a dilute suspension, this result can be compared with a weakly birefringent and dichroic material. In this case, from equations (2.15) and (2.21),... 

S. J. Johnson, P. L. Frattini and G. G. Fuller, Simultaneous dichroism and birefringence measurements of dilute colloidal suspensions in transient shear flow, J. Colloid Interface Sci., 104,440 (1985) S. J. Johnson and G. G. Fuller, Flowing colloidal suspensions in non-Newtonian suspending fluids decoupling the composite birefringence, Rheol. Acta, 25, 405 (1986). 

N J. Wagner, G.G. Fuller, and W.B. Russel, The dichroism and birefringence of a hard-sphere suspension under shear, J. Chem. Phys., 89,1580 (1988). 

B. Higher Harmonics Generation in Field-Induced Birefringence by a Suspension of Rigid Dipoles Zero Bias Field... 

The goal of the following discussion is to study the low-frequency dynamic birefringence induced by an alternating field in a suspension of acicular particles with dipole moments, that is, the system of type 1 according to the classification given above. The results presented are obtained avoiding any... 

Depending on the scheme chosen, the birefringence experiments provide [143,144] direct measurements of either Av or (Av)2. To present the theoretical results in a form suitable for comparison with the experimental data, let us consider the orientational oscillations induced in the dipolar suspension by a harmonic held H = Hq cos (at and analyze the frequency dependencies of the spectra of the order parameters (P2) and (Pi)2- As formula (4.371) shows, the latter quantities are directly proportional to Av and (Av)2, respectively. Since the oscillations are steady, let us expand the time-dependent orientational parameters into the Fourier series... 

The investigation of the electric birefringence is an excellent tool for the study of the PPP polyelectrolytes because this method is highly sensitive and therefore particularly suited for very dilute solutions [40-42]. At low field strength, the birefringence observed in solutions or suspensions of non-interacting molecules or particles rises with the square of field strength (Kerr s law) and in proportion with concentration [43] ... 

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