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RESEARCH PRODUCT
Thickness and temperature dependent structure of Cd arachidate Langmuir-Blodgett films
R. M. KennHelmuth MöhwaldP. Tippmann-krayersubject
DiffractionPhase transitionGrazing incidence diffractionbusiness.industryChemistryMetals and AlloysSurfaces and InterfacesLangmuir–Blodgett filmSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsCrystallographyOpticsMonolayerMaterials ChemistryWave vectorHexagonal latticeOrthorhombic crystal systembusinessdescription
Abstract The structure of monolayers of Cd arachidate on water and on solid support, and the thickness dependent changes when building up a multilayer via the LB technique are studied by means of grazing incidence diffraction of X-ray. In monolayers the perpendicularly oriented amphiphilic molecules are arranged in a hexagonal lattice, whereas for thicker layers (even for three layers) they crystallize in an orthorhombic unit cell with a reduced molecular are ( A = 18.2 A 2 ) compared to that of the monolayer ( A = 19.7 A 2 ). In-plane diffraction measurements with wave vector transfer perpendicular to the surface (rod scans) could prove for multilayers a maximum tilt angle of 2°. The data prove orientational as well as positional correlation between adjacent monolayers. For multilayers, a thermally induced phase transition accompanied by an expansion of the lattice from an orthorhombic ( A = 18.2 A 2 ) to a hexagonal ( A = 19.7 A 2 ) lattice is found. This structural change is reversible below 110 °C.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1992-04-01 | Thin Solid Films |