INVESTIGADORES
VACA CHAVEZ FORNASERO Fabian
artículos
Título:
Pore size distributions in polyelectrolyte multilayers determined by nuclear magnetic resonance cryoporometry
Autor/es:
FABIAN VACA CHAVEZ; MONICA SCHOENHOFF
Revista:
JOURNAL OF CHEMICAL PHYSICS
Editorial:
AMER INST PHYSICS
Referencias:
Lugar: New York; Año: 2007 vol. 126 p. 104705 - 104707
ISSN:
0021-9606
Resumen:
Polyelectrolyte multilayers PEMs are thin films, which are assembled one molecular layer at a time, by alternatingly adsorbing polycations and polyanions making use of their attractive electrostatic interaction. Since the porosity of PEMs is one of the properties of major interest, in the current work the first pore size distribution of PEMs in samples consisting of silica particles coated with polyallylamine hydrochloride and polysodium 4-styrenesulfonate is presented. To this end, the nuclear magnetic resonance NMR cryoporometry technique was applied. The proton NMR signal of liquid water is analyzed assuming a log normal distribution of motional correlation times. From the results, it is possible to determine the size of water sites in the layers to around 1 nm. In addition, a slight variation with the number of layers is found. The average pore size agrees with cutoff sizes found in permeation experiments.
