info:eu-repo/semantics/article
Molecular orientation in self-assembled multilayers measured by Second Harmonic generation using femtosecond pulses
Fecha
2009-06Registro en:
Von Bilderling, Catalina; Tagliazucchi, Mario Eugenio; Calvo, Ernesto Julio; Bragas, Andrea Veronica; Molecular orientation in self-assembled multilayers measured by Second Harmonic generation using femtosecond pulses; Optical Society of America; Optics Express; 17; 13; 6-2009; 10642-10647
1094-4087
CONICET Digital
CONICET
Autor
Von Bilderling, Catalina
Tagliazucchi, Mario Eugenio
Calvo, Ernesto Julio
Bragas, Andrea Veronica
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.