Planar and non-planar solidification of optically organised smectic films

• Published in: Liquid crystals 2011-05, Vol.38 (5), p.575-579
• Main Authors: Vasseur, H., Djellab, K.
• Format: Article
• Language: English
• Subjects: Ambient temperature; freely suspended films of smectic phase; Freezing; Frozen; Homogeneity; homogeneous optical properties; homogeneous solid; LCDs; Liquid crystal displays; Liquid crystals; Liquid films; new freezing process; Optical properties; Spreading; Temperature effects; Thin films
• ISSN: 0267-8292; 1366-5855
• DOI: 10.1080/02678292.2011.558219

This letter describes an original freezing process that yields homogeneous solid films at ambient temperature with preservation of the layered structure of the chiral smectic phase. One of the most remarkable features of the process is its ability to provide complexly bent films with arbitrary three-dimensional shapes. Their optical homogeneity is observed in the planar as well as in the bent films. The method is very simple. After forming the films by spreading the liquid crystal above a hole in a glass slice placed over a hot stage, the film is heated from below. The hot film is exposed to ambient temperature. Then, a solid object at room temperature with a specifically adapted shape is immersed in the liquid film. The mechanical constraints imposed by the object curves the film and stabilises various solid two- and three-dimensional structures. Their homogeneous optical properties are due to long-range organisation of the molecular orientation (tilt), which combines with a complex helical arrangement of the frozen smectic layers.