| Abstract
| - A small-angle light scattering (SALS) technique together with optical microscopy observation are used toinvestigate phase separation kinetics in films of low molecular weight thermotropic liquid crystal (4-cyano-4‘-n-octyl-biphenyl, 8CB) with flexible polymer (polystyrene, PS). The growth of domains is studied as afunction of time, film thickness, and film composition. The light scattering results are correlated with theimages obtained by optical microscopy observation. In this paper, we study the breaking of a bicontinuousnetwork of polymer in liquid crystal into droplets and their further growth via the coalescence-inducedcoalescence mechanism. The appearance of droplets in the system leads to a strong scattering at small wavevectors, while the bicontinuous network gives a peak at a nonzero wave vector. Superposition of these scatteringintensities leads to the appearance of a second peak in the full scattering intensity signal, when the bicontinuousnetwork starts to break up into disjointed elongated domains. Finally, both peaks merge into a single peak,which moves quickly toward zero wave vectors, indicating a complete transformation of elongated domainsinto spherical droplets of variable size. We found that the separation process does not depend on the size ofthe system. Irrespective of the sample thickness, the network breaks into fragments always at the same timeafter temperature quench. On the basis of morphological analysis, we found that the average size of thedroplets which formed from the network grows with time, t, as tα, α = 0.9 ± 0.1, in the isotropic phase andin the nematic phase.
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