LATE-TIME COARSENING DYNAMICS IN A NEMATIC LIQUID-CRYSTAL

We have studied the coarsening dynamics of line defects in the uniaxial nematic liquid crystal 4-cyano-4'-n-pentylbiphenyl, subjected to a rapid pressure jump from the isotropic to the nematic phase. At late times, the density of disclination lines rho is expected to scale with time as rho is-proportional-to t -v with v = 1. We have measured the scaling exponent to be v = 1.02 +/- 0.09 over the region 16 < rho < 160 mm -2. In addition, we have measured the collapse of loops consisting of type-1/2 disclination lines. The loop radius r is expected to scale with time as r is-proportional-to (t0 -t)alpha, where alpha = 1/2 and t0 is the time at which the loop vanishes. We found alpha to be 0.50 +/- 0.03.