Organization and orientation of amphiphilic push-pull chromophores deposited in Langmuir-Blodgett monolayers studied by second harmonic generation and atomic force microscopy.
Orientation and organization of two amphiphilic push-pull chromophores mixed with two phospholipids (dipalmitoylphosphatidylcholine and dioleoylphosphatidylcholine) in Langmuir-Blodgett (LB) monolayers are investigated by second harmonic generation. The LB monolayers have also been characterized by atomic force microscopy and UV-vis spectroscopy. The effective molecular orientations and hyperpolarizabilities of the chromophores are studied as a function of the phospholipid concentrations. The experimental results are discussed within the frame of a model of orientational distribution of the chromophores which gives the orientational mean angle and bounds on the orientational disorder. The mean orientation of the chromophores is found to be within 45-55 degrees whereas their hyperpolarizability coefficients, measured with respect to quartz, are estimated to be in the range (0.3-0.7) x 10(-27) esu taking account of the maximal orientational disorder.
Leray
A
A
GMCM, CNRS UMR 6626, Institut de Physique de Rennes, and SESO, CNRS UMR 6510, Institut de Chimie de Rennes, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.
Leroy
L
L
Le Grand
Y
Y
Odin
C
C
Renault
A
A
Vié
V
V
Rouède
D
D
Mallegol
T
T
Mongin
O
O
Werts
M H V
MH
Blanchard-Desce
M
M
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force / Q000379:methods*; D015394:Molecular Structure; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013499:Surface Properties
D004396:Coloring Agents; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D015060:1,2-Dipalmitoylphosphatidylcholine; C017251:1,2-oleoylphosphatidylcholine