A low volume fraction gel structure can strongly perturb the ordered phases of liquid crystals. High resolution x-ray diffraction and ac-calorimetric experiments have been carried out on various liquid crystals embedded in gels. Results will be presented for the nematic--smectic-A, the smectic-A--smectic-C and the isotropic--smectic-A transitions. Positional ordering is observed to be systematically modified while the tilting transition is oblivious to confinement. Quantitative comparisons are made with the random-field model (Imry and Ma) and with the anomalous elasticity model (Radzihovsky and Toner). M.K. Ramazanoglu et al., cond-mat/0311635
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..