Related Experiment Videos
Anisotropic surface melting in lyotropic cubic crystals. Part 1: Pn3m/L1 interface, poor faceting
J Grenier1, T Plötzing, D Rohe
1Laboratoire de Physique des Solides, Université Paris-Sud, Bât. 510, 91405, Orsay Cedex, France.
The European Physical Journal. E, Soft Matter
|March 1, 2006
Summary
Anisotropic surface melting, observed in ice and metal crystals, also occurs in lyotropic systems like C12EO2/water mixtures. This phenomenon involves crystal facets remaining dry while rough surfaces are wetted by liquid layers.
Area of Science:
- Materials Science
- Physical Chemistry
- Soft Matter Physics
Background:
- Crystalline solids exhibit anisotropic surface melting near phase transitions.
- Lyotropic systems, such as surfactant/water mixtures, form complex liquid crystalline phases.
Purpose of the Study:
- To investigate anisotropic surface melting in lyotropic systems.
- To characterize the interfacial behavior of the C12EO2/water mixture near its peritectic triple point.
Main Methods:
- Direct observation using optical microscopy.
- Analysis of interfacial structures and phase coexistence.
Main Results:
- Anisotropic surface melting was confirmed in the C12EO2/water system near the Pn3m/L3/L1 triple point.
- Above the triple point, Pn3m crystal surfaces showed dry (111) facets and rough, L3-wetted surfaces.
- Below the triple point, a thick L3 layer grew from the rough interface, while facets remained dry and receded.
Conclusions:
- Lyotropic systems display anisotropic surface melting analogous to crystalline solids.
- The observed interfacial behavior is governed by the coexistence of Pn3m, L3, and L1 phases.
- Constant mean curvature surfaces describe the L3/L1 and L3/Pn3m interfaces in the tri-phasic region.