Small-angle light scattering and transmittance of polymer film, containing liquid crystal droplets with inhomogeneous boundary conditions

Experimental results and theoretical model to describe angular dependence of light scattering by monolayer of nematic droplets

“…n e (x) is the local refractive index for extraordinary wave in point x=x(y,z), n o is the coordinateindependent refractive index for ordinary wave equal to the ordinary refractive index of LC, ⊥ n x Δ is the longitudinal (along the wavevector of incident wave) size of LC droplet elementary volume in which liquid crystal orientation structure is assumed as uniform and determined by only molecular order parameter [7,[22][23][24]…”

“…(14)- (16), is the extraordinary refractive index of liquid crystal, n x , n y , and n z are the Cartesian components of local director n(r)=(n x , n y , n z ). In case of identical director configuration [7] inside droplets and uniform distribution of LC droplet bipolar axes over the angle, we can write the average components of the vector amplitude scattering function and their squared absolute values (see Eqs. (1) and (2)) as follows: …”

“…This issue becomes even more complicated if to consider liquid crystal (LC) droplets [2][3][4][5][6][7], for example, polymer-dispersed liquid crystal (PDLC) films because orientation structure within the droplets is commonly inhomogeneous. Configuration of LC director (a unit vector n characterizing preferred molecular orientation for a local volume in a droplet) can be rather complicated [2,3,7]. Consecutive development of special simulation techniques by many research groups (see, for instance, the lists of some of them in [6,7]) allows now calculating adequately the light scattering pictures for actual LC dispersions.…”

“…Configuration of LC director (a unit vector n characterizing preferred molecular orientation for a local volume in a droplet) can be rather complicated [2,3,7]. Consecutive development of special simulation techniques by many research groups (see, for instance, the lists of some of them in [6,7]) allows now calculating adequately the light scattering pictures for actual LC dispersions.…”

Model to describe light scattering by polymer film containing droplets with inhomogeneous anchoring of liquid crystal molecules at the polymer–droplet interface: asymmetry effect in the angular distribution of light

“…The effect consists in the fact that in the scattering plane (the plane defined by the wave vectors of the incident and scattered waves) the values of intensities of radiation scattered at angle +θs and angle θs (see Fig.1) are different relative to the illumination direction. Some preliminary data on the effect are given in [29][30][31]. It is worth noting that in films with homogeneous surface anchoring there is a symmetrical distribution of the radiation intensity scattered at the angles +θs and θs [1,2,[29][30][31].…”