Morphology transitions in a liquid crystal

We describe experimental investigations of the crystallization of the liquid crystal 10 OCB. Undercoolings as large as 40 degrees C can be achieved, allowing ready access to both the diffusive and kinetic regimes. As we vary the undercooling, we see seven distinct solidification modes. Most of the transitions between modes are sharp, allowing one to view them as dynamical analogs of phase transitions. We see strongly first order, weakly first order, and continuous morphology transitions. Contrary to widespread speculation. when two modes compete, the faster one does not always win out. (C) 1998 Elsevier Science B.V. All rights reserved.