Stable ordering in Langmuir-Blodgett films.
Defects in the layering of Langmuir-Blodgett (LB) films can be eliminated by depositing from the appropriate monolayer phase at the air-water interface. LB films deposited from the hexagonal phase of cadmium arachidate (CdA2) at pH 7 spontaneously transform into the bulk soap structure, a centrosymmetric bilayer with an orthorhombic herringbone packing. A large wavelength folding mechanism accelerates the conversion between the two structures, leading to a disruption of the desired layering. At pH > 8.5, though it is more difficult to draw LB films, almost perfect layering is obtained due to the inability to convert from the as-deposited structure to the equilibrium one.
Takamoto
D Y
DY
Department of Chemical Engineering and Materials, University of California, Santa Barbara, CA 93106, USA.
Aydil
E
E
Zasadzinski
J A
JA
Ivanova
A T
AT
Schwartz
D K
DK
Yang
T
T
Cremer
P S
PS
D002104:Cadmium / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004537:Eicosanoic Acids / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers; D018625:Microscopy, Atomic Force; D013057:Spectrum Analysis; D013229:Stearic Acids / Q000737:chemistry*; D013816:Thermodynamics; D014783:Viscosity
D004537:Eicosanoic Acids; D005227:Fatty Acids; D008051:Lipid Bilayers; D013229:Stearic Acids; D002104:Cadmium; C031183:stearic acid; C010210:lignoceric acid