Synchrotron studies of the first-order melting transitions of hexatic monolayers and multilayers in freely suspended liquid-crystal films

Journal Article · Tue Feb 28 23:00:00 EST 1989 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.39.2703· OSTI ID:6227867

Amador, S; Pershan, P S; Stragier, H; Swanson, B D; Tweet, D J; Sorensen, L B; Sirota, E B; Ice, G E; Habenschuss, A

Synchrotron x-ray diffraction has been used to study the surface and the interior hexatic-to-liquid (smectic-I to smectic-C) melting transitions of freely suspended liquid-crystal films of N-(4'-(n-heptyl)benzylidene)-4-(n-heptyl)aniline (7O.7) five molecular layers thick. Both the surface hexatic monolayers and the interior hexatic layers melt via hysteretic first-order transitions. After the two surface layers undergo a first-order transition to the smectic-I phase, the surface hexatic correlation length xi evolves smoothly from approx.100 to approx.300 A with a roughly square-root form, xiapprox.chemically bondT-T/sub c/chemically bond/sup 1/2/.

• Research Organization: Division of Applied Sciences and Department of Physics, Harvard University, Cambridge, Massachusetts 02138
• OSTI ID: 6227867
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 39:5; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
BREMSSTRAHLUNG
COHERENT SCATTERING
CRYSTALS
DIFFRACTION
ELECTROMAGNETIC RADIATION
FILMS
FLUIDS
LIQUID CRYSTALS
LIQUIDS
MELTING
ORGANIC COMPOUNDS
PHASE TRANSFORMATIONS
RADIATIONS
SCATTERING
SYNCHROTRON RADIATION
THIN FILMS
X-RAY DIFFRACTION