Ellipsometric porosimetry

Boissiere, C. Grosso, D. Lepoutre, S. Nicole, L. Bruneau, A. B. Sanchez, C. 2005. Porosity and mechanical properties of mesoporous thin films assessed by environmental ellipsometric porosimetry. Langmuir 21 12362-12371. 

The pore characteristics of the film were studied using Positron Annihilation Lifetime Spectroscopy (PALS) [4] by Prof. Gidley at University of Michigan. It was fi>und that all pores were intercoimected, and the average pore diameter was 2.2 run. Porosity was measured as 53% using Ellipsometric Porosimetry (EP) [15. /6]atIMEC. 

The premise of X-ray porosimetry is analogous to ellipsometric porosimetry ( P) [7], which also uses the capillary condensation of organic vapors to map out adsoiption/desorption isotherms. However, EP tracks... 

Structure (1-100 (itn). An acidreactive modification of the polymer blend film converted part of the organic template to a sUica network through exposure to precursor vapors. The impact of the polymer blend composition on the structure of the porous silica films was examined with the stmcture of the porous silica films determined using X-ray diffraction (XRD), SEM, transmission electron microscopy (TEM), spectroscopic ellipsometry (SE), and ellipsometric porosimetry (EP). 

Ellipsometric porosimetry was performed using toluene as a probe molecule to provide information regarding pore size distribution. The films were exposed to controlled relative pressures of toluene, and the change in refractive index during the vapor adsorption/desorption provided detailed information regarding pore filling [55]. In order to estimate the pore size distribution (PSD), adsorption/ desorption curves were fitted, after which the Kelvin equation was applied. As a result, a pore size distribution was obtained which demonstrated the presence of nanopores in the silica films (Figure 9.5). 

As regards pore size, Sakatani et al. [72] obtained mesostructured TiOa coatings with cubic structure between 300 and 800 °C. With ellipsometry and environmental ellipsometric porosimetry (EEP), they foimd pore volumes of 40% and... 

On this basis, a rapid and nondestructive method, ellipsometric porosimetry (EP), has been developed in which adsorption-desorption isotherms are determined from the variations of film refractive index efr induced by the change of partial pressme of a solvent above a film. The setup combines a pressure-controlled chamber (conventional gas volumetric characterization devices) and a classical eUipsometer thus, HeS is determined for each vapor pressure and is a direct measme of the adsorption isotherm. A typical example is shown in Figure 33.3a for a Si02 templated with CTAB thin film (Martinez Ricci, M.L., Fuertes, M.C., Violi, I.L., Grosso, D., and Soler lUia, G.J.AA., Rational design of mesoporous films for synthesis of responsive Bragg reflectors (unpublished).). The refractive index increases from eff (630 nm) = 1.21, for a large fraction of air inside micropores and/or mesopores within the silica nanostructure, to (630 nm) = 1.37 when pores are saturated with water. The steep increase at intermediate vapor pressures is associated with the capillary condensation inside pores. The hysteresis in the desorption branch is due to the presence of water in the necks that join pores, whose effective radii are smaller than the pore radius. 

Fuertes, M.C., Barrera, M.P., and P14, J. (2012) Sorption and optical properties of sol-gel thin films measured by X-ray reflectometry and ellipsometric porosimetry. Thin Solid Films, 520, 4853-4862. 

Baklanov, M.R., Mogilnikov, K.P., Polovinkin, V.G., and Dultsev, F.N. (2000) Determination of pore size distribution in thin films by ellipsometric porosimetry. 

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