Morphology of Polymer/Liquid-Crystal Nanotubes: Influence of Confinement

• Published in: Advanced functional materials 2005-10, Vol.15 (10), p.1656-1664
• Main Authors: Steinhart, M., Murano, S., Schaper, A. K., Ogawa, T., Tsuji, M., Gösele, U., Weder, C., Wendorff, J. H.
• Format: Article
• Language: English
• Subjects: discotic; Liquid crystals; Liquid crystals, discotic; Nanotubes; Nanotubes, organic; organic; Template-assisted synthesis
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200500139

Polymer/liquid‐crystal (LC) tubes consisting of an approximately 30 nm thick poly(methyl methacrylate) (PMMA) layer on the outside and a 5 to 10 nm thick discotic liquid‐crystalline layer on the inside of the tube walls have been prepared by wetting ordered porous alumina templates with a pore diameter of 400 nm. Decreasing the pore diameter to 60 nm results in a confinement‐induced transition from a wetting state to a non‐wetting state, and solid rods with a sequential morphology are obtained. The texture of the mesophase depends on the morphology type and the thermal history. Under certain conditions the LC mesophase exhibits a dominant, well‐ordered planar texture where the discotic columns are aligned with the long axes of the tubes. The controlled generation of one‐dimensional nano‐objects possessing mesoscopic fine structures and intrinsic anisotropy should be the first step towards a rational design of miniaturized building blocks. Polymer/liquid‐crystal nanotubes with an outer polymer and an inner discotic liquid‐crystal layer (see Figure) can be fabricated by exploitation of phase separation and interfacial phenomena. The morphology and the texture depend on the thermal history and the properties of the employed templates. These structures are promising start for developing miniature device components.