X-ray Nanoscale Profiling of Layer-by-Layer Assembled Metal/Organophosphonate Films

Autor: SonBinh T. Nguyen, Chian Liu, Ray Conley, Joseph A. Libera, Joseph T. Hupp, Michael J. Bedzyk, Richard W. Gurney
Rok vydání: 2004
Předmět:
Zdroj: Langmuir. 20:8022-8029
ISSN: 1520-5827
0743-7463
DOI: 10.1021/la048904b
Popis: The nanoscale structure of multilayer metal/phosphonate thin films prepared via a layer-by-layer assembly process was studied using specular X-ray reflectivity (XRR), X-ray fluorescence (XRF), and long-period X-ray standing wave (XSW) analysis. After the SiO(2) X-ray mirror surfaces were functionalized with a monolayer film terminated with phosphonate groups, the organic multilayer films were assembled by alternating immersions in (a) aqueous solutions containing Zr(4+), Hf(4+), or Y(3+) cations and then (b) organic solvent solutions of PO(3)-R-PO(3), where R was a porphyrin or porphyrin-square spacer molecule. The different heavy metal cations provided X-ray fluorescence marker layers at different heights within the different multilayer assemblies. The XSW measurements used a 22 nm period Si/Mo multilayer mirror. The long-period XSW generated by the zeroth-order (total external reflection) through fourth-order Bragg diffraction conditions made it possible to examine the Fourier transforms of the fluorescent atom distributions over a much larger q(z)() range in reciprocal space than previously achieved.
Databáze: OpenAIRE