Anticlinic-synclinic transitions in superthin free-standing smectic films
P. V. Dolganov, G. Joly+, P. Cluzeau*, V. K. Dolganov, C. Gors+, H. T. Nguyen*
Institute of Solid State Physics RAS, 142432 Chernogolovka, Moscow Region, Russia
+Laboratoire de Dynamique et Structures des Matériaux Moleculaire, Université de Lille 1, 59655 Villeneuve d'Ascq, France
* Centre de Recherche Paul Pascal, CNRS, 33600 Pessac, France
PACS: 61.30.-v, 64.70.Md, 61.30.Gd
Abstract
Anticlinic-synclinic transition was studied in superthin smectic
films using polarized light reflected microscopy. The measurements
were made in a compound exhibiting the SmCFI1* subphase in a
narrow temperature interval between antiferroelectric SmCA*
and ferroelectric SmC* phases. In films we observed series of
transitions which numbers increases with increasing film
thickness. Surface ordering leads to increasing transition
temperatures with decreasing film thickness and to change of
orientation of the molecular tilt plane in layers. Succession of
transitions results from the competition between the surface and
the bulk ordering. We found that line string defects may form in
film, their orientation and collective behavior result from
elastic deformation of molecular ordering.