Abstract
The short-range order which remains when the isotropic to smectic-[Formula presented] transition is perturbed by a gel of silica nanoparticles (aerosils) has been studied using high-resolution synchrotron x-ray diffraction. The gels have been created in situ in decylcyanobiphenyl, which has a strongly first-order isotropic to smectic-[Formula presented] transition. The effects are determined by detailed analysis of the temperature and gel density dependence of the smectic structure factor. In previous studies of the continuous nematic to smectic-[Formula presented] transition in a variety of thermotropic liquid crystals the aerosil gel appeared to pin, at random, the phase of the smectic density modulation. For the isotropic to smectic-[Formula presented] transition the same gel perturbation yields different results. The smectic correlation length decreases more slowly with increasing random-field variance in good quantitative agreement with the effect of a random pinning field at a transition from a uniform phase directly to a phase with one-dimensional translational order. We thus compare the influence of random fields on a freezing transition with and without an intervening orientationally ordered phase.
| Original language | English |
|---|---|
| Pages (from-to) | 8 |
| Number of pages | 1 |
| Journal | Physical Review E |
| Volume | 69 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2004 |
| Externally published | Yes |