INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Molecular orientation in self-assembled multilayers measured by Second Harmonic generation using femtosecond pulses
Autor/es:
CATALINA VON BILDERLING; MARIO TAGLIAZUCCHI; ERNESTO J. CALVO; ANDREA V. BRAGAS
Revista:
OPTICS EXPRESS
Editorial:
Optical Society of America
Referencias:
Año: 2009 vol. 17 p. 10642 - 10642
ISSN:
1094-4087
Resumen:
We present measurements of the optical second-harmonic generation in self assembled multilayer films of PAZO/PAH polymers with the aim to investigate molecular order in the layer-by-layer architecture. The experiments are performed in transmission, using a femtosecond Ti:Sa pulsed laser, which allows a more accurate determination of the amplitude of the second harmonic signal, without interference fringes usually present in nanosecond experiments. We found that the first bilayer, in contact with the substrate, presents a broad distribution of the orientation of the molecules, while the addition of successive bilayers (up to 12) produces ordering of the molecules with a small tilt angle respect to the surface normal. This result, together with the monotonic increment of the second harmonic signal with the number of layers indicates that the molecules grow orderly assembled in these films