Related Experiment Video
Updated: May 30, 2026
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Isotropic-nematic transition at the surface of a liquid crystal embedded in an aerosil network
Satoshi Aya1, Yuji Sasaki, Fumito Araoka
1Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Meguro, Tokyo, Japan.
Abstract:
We reexamined the isotropic-nematic (Iso-N) phase transitions of 4-n-heptyl cyanobiphenyl (7CB) embedded in aerosils of silica nanoparticle dispersions using highly sensitive differential scanning calorimetry (HS-DSC), polarizing optical microscopy (POM), and retardation measurements. We found a simple and very profound relationship between the calorimetric and optical measurements; in addition to double DSC peaks, which have been observed previously, a two-step change of the retardation was clearly observed by varying temperature. From our analysis, there is no doubt that the Iso-N liquid-crystal phase transition certainly occurs in two steps, i.e., the bulk transition takes place at first and then the surface transition takes place upon cooling. We should note that the surface transition takes place below the bulk transition temperature, the opposite of what was recently observed in a polymer-dispersed liquid-crystal system.
