Focal conic loop

FIGURE 16 Free energy of a focal conic loop in the thin film shown in Fig. 15 as a function of the loop radius, a, for three field strengths E < , < Ey The critical radius (a ) and activation energy (AF ) are shown for E = Ey... 

Another possible alignment mechanism is through nucleation of focal conic loops. Hareng et al. [35] demonstrated this phenomenon in a smectic A liquid crystal that was originally well aligned. Adopting the analysis by Lavrentovich and Kleman [36], the activation energy for this process in the PS-PMMA block copolymers is on the order of... 

FIGURE 15 A smectic A thin film between substrates with planar anchoring. The easy axis is vertical, and the layer planes are shown. A focal conic defect is shown in cross. section. The +1 /2 disclination loop is indicated. (Adapted from Ref. 35.)... 

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