Gas transport through supported Langmuir-Blodgett multilayers

Transport properties of water and pentane in Langmuir–Blodgett films

“…We show that the uptake of vapors into LB films are affected by aging and annealing of the films. The effect of deposition conditions, aging, annealing, as well as the fabrication of pin-hole free layers (Gaines and Ward, 1977;Rose and Quinn, 1968;Albrecht et al, 1984) all need to be investigated further.…”

“…As shown in Figure 5 the data for both thicknesses collapse on each other; this, as well as the linearity of the data at short times, indicate Fickian diffusion (Crank, 1956). Previous studies using the permeation method to determine the transport properties of LB films found that the permeability of LB films varied with the number of layers (Gaines and Ward, 1977;Albrecht et al, 1984;Rose and Quinn, 1968; Bruinsma and Stroeve, 1994). As explained previously, this is probably due to the sensitivity of the permeation method to pin hole defects in the films.…”

“…Thus composites made of a permeable polymer coated with an LB film could serve as practical membranes. The polymer would provide the mechanical support while the LB film would be used to control selectivity and allow high permeation rates (Gaines and Ward, 1977;Rose and Quinn, 1968;Conner et al, 1993;Albrecht et al, 1984;Bruinsma and Stroeve, 1994;Kim et al, 1989;Osiander et al, 1988).…”

“…A pressure gradient is applied across the film and the resulting flux through the film is measured. This type of rate measurement is, however, greatly affected by the presence of any small holes in the film; and indeed it was observed (Rose and Quinn, 1968;Gaines and Ward, 1977;Albrecht et al, 1984) that the measured permeability of LB films depended on the thickness, that is, number of layers. In contrast, the sorption method, which we use in this work, requires no pressure differential across the film, and thus has the advantage that measurements are relatively insensitive to the presence of pin holes (Crank and Park, 1968).…”

Studies on the Diffusion of Molecules through Pores in Monolayer and Multilayer Films

“…Some of the applications are based on use of downstream through the pore to the next monolayer. The structured multilayer films, such as those produced by the net rate of change of activated molecules coverage, du*/ Langmuir-Blodgett (LB) technique (10,11). Langmuirdt, comprising the above processes, is derived, to include Blodgett films can have pore sizes that are of the order of porosity effects on the diffusion through ultrathin films: the molecular size (6,8).…”