Desorption from slightly soluble decanol monolayers

Barrier kinetics of adsorption–desorption of alcohol monolayers on water under constant surface tension

“…This regime leads again to a linear dependence ln(A0/A)  t, but the coefficient in it is related to the energy barrier for the transfer from the monolayer to the subsurface. This behaviour is typical for very large adsorbates (proteins, nanoparticles); however, Baret et al found a significant effect from the barrier process already for decanol [6]. De Keyser and Joos [9] plainly repudiated the work of Baret et al.…”

“…A common application [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] of the Langmuir trough is to follow the process of desorption of a spread monolayer of slightly soluble amphiphile under isobaric conditions, where the decrease of the area A of the film with time t is monitored at constant surface pressure  S ( S = 0 , where 0 and are the surface tensions of the pure solvent and of the monolayer). The isobaric regime has been used for determination of the diffusion coefficient D of the surfactant [5] and for evaluation of its solubility [11]; to study the dissociation and the Hofmeister effect on the properties of monolayers of adsorbed acids [7]; to study the processes involved in the collapse of the monolayer [8,12]; phase transitions [14] in monolayers; interaction between adsorbed lipids and proteins [10]; and generallythe mechanism of desorption [4,6,9]. Recently, we used the isobaric regime as an auxiliary experiment to correct the  S vs. A isotherms for the material loss due to dissolution of the monolayer [17] (similarly to Motomura et al [18]).…”

“…A third regime has been reported to operate at short times [6]: while the diffusion layer is still thin, the rate determining process is the flip-flop-like desorption of surfactant from the monolayer to the solvent (d-regime, barrier control). This regime leads again to a linear dependence ln(A0/A)  t, but the coefficient in it is related to the energy barrier for the transfer from the monolayer to the subsurface.…”

Self-Assembly Monolayer Structures of Lipids and Macromolecules at Interfaces

“…The desorption of slightly soluble components from pure monolayers has been studied quantitatively by many workers (Heikkila et al, 1950;Davies, 1951aDavies, ,b, 1952Saraga, 1955;Brooks and Alexander, 1960;Gershfeld, 1964;Gaines, 1966;Petlak and Gershfeld, 1967;Gonzales and MacRitchie, 1970;Patil et al, 1973;Baret et al, 1975). The kinetics of adsorption are best followed by measurements of the decrease of surface area, A, as a function of time, t, at constant surface pressure, At a given the monolayer establishes rapid equilibrium with thin layers (several molecular diameters in thickness) adjacent to the surface.…”

“…An important element was considered by one of the investigators (Baret et al, 1975). The plot is linear and the value of A is 22 Å from the slope.…”