F. Gonzalezcaballero et Ml. Kerkeb, SYNERGISM AT A LIQUID-SOLID INTERFACE - ADSORPTION OF BINARY-MIXTURESOF BILE-SALTS ONTO A CHOLESTEROL SURFACE, Langmuir, 10(4), 1994, pp. 1268-1273
The nonideal solution treatment of molecular interactions in binary mi
xtures of surfactants at a solid-liquid interface elaborated by Rosen
et al. has been used to study the synergetic phenomena that can take p
lace at the cholesterol-bile salt solution interface. The three binary
combinations of sodium cholate (NaC), sodium deoxycholate (NaDC), and
sodium chenodeoxycholate (NaCDC) in aqueous solution were investigate
d. Synergism was found in NaC-NaDC and NaC-NaCDC mixtures, and no syne
rgetic effect was detected for the NaDC-NaCDC mixture. For all the sys
tems studied there was consistency between synergism found at the solu
tion-air and at cholesterol-solution interfaces. Values of the molecul
ar interaction parameter, beta, at the solution-air and at the cholest
erol-solution interface were also calculated. The small values of \bet
a\ in the three binary systems, especially in the NaDC-NaCDC mixture,
reflect a weak interaction between the surfactant molecules at the int
erface. This was ascribed to the similar molecular structures of these
surfactants.