FIG. 15 Distribution of surfactant solution concentration inside a hydrophobic capillary, C(x), and in adsorbed layer on capillary surface, a(x), during imbibition of the solution at C <C=CMC.

doi:10.1201/9780203021262-100

Chapter

FIG. 15 Distribution of surfactant solution concentration inside a hydrophobic capillary, C(x), and in adsorbed layer on capillary surface, a(x), during imbibition of the solution at C <C=CMC.

Chapter

ABSTRACT

Since the rate of imbibition of surfactant solutions into a hydrophobed capillary is rather slow, the kinetics of adsorption may be ignored and it is possible to include into Eq. (19) an equilibrium adsorption isotherm a=f(C). As a first approximation, the linear form of the isotherm will be used here:

a(x, t)=(2/r)G1C(x, t)=F1C(x, t), (20)

where G1 is Henry’s constant contained in the adsorption equation Γ=G1C (g/cm2). In the case of a cylindrical capillary, a=2Γ/r.