INFLUENCE OF 1-DECANOL ON THE SURFACE-TENSION AND WETTING POWER OF A NEW ANIONIC SURFACTANT DERIVED FROM SUGAR

We studied the adsorption behaviour at the liquid/air and liquid/solid interface of a new anionic surfactant derived from sugar, the sodium decyl galacturonate. The surface tension of aqueous solutions, measure d in equilibrium and as a function of time, is particularly affected b y the presence of decanol, synthesis residue, which amount ranges betw een about 0 and 13%. The surface tension lowering is accelerated in pr esence of decanol, owing to its rapid diffusion to the interface or/an d because it affects the mobility and adsorption process of the anioni c surfactant molecules. The wetting power of surfactant solutions were also investigated in relation with textile treatment applications. We measured the kinetics of absorption of surfactant solutions in a piec e of standard cotton and compared it to the absorption of pure decanol , a completely wetting liquid and to the absorption of an alkylpolyglu coside. The time at which the fabric piece is saturated appears to be related to the adsorption of surface-active molecules on the fibers at the advancing liquid front/fabric contact line. Decanol was found to promote absorption and micellar life-time seem to reflect the differen ces observed at high concentration. This study shows the importance of controlling the amount of surface-active residues which may alter the kinetics of surfactant adsorption, particularly in industrial process es where equilibrium conditions are not reached.