Synthesis and Surface Properties of N-Alkyl-N-methylgluconamides and N-Alkyl-N-methyllactobionamides

Equilibrium Surface Tension, Dynamic Surface Tension, and Micellization Properties of Lactobionamide-Type Sugar-Based Gemini Surfactants

“…Table 1 lists the corresponding values for 2C n Lac and C n MLA. The pC 20 values of 2C n Lac were much higher than those of C n MLA with the same chain length, and they increased with an increase in alkyl chain length. These results indicated that the higher the number of chains or the longer the chain, the higher is the adsorption of molecules at the air-water interface.…”

“…The pC 20 and cmc/C 20 ratio 13 values, which are often used to estimate the adsorption and aggregation properties of surfactants, represent the efficiency of surfactant adsorption at the air-water interface and the effectiveness that can be correlated with structural factors regarding the adsorption and micellization processes, respectively. Here, C 20 represents the surfactant concentration required to reduce the surface tension of water by 20 mN m 1 .…”

“…Here, C 20 represents the surfactant concentration required to reduce the surface tension of water by 20 mN m 1 . The larger the value of pC 20 , the greater is the tendency of the surfactant to adsorb at the air-water interface. The larger the value of the cmc/C 20 ratio, the greater is the tendency of the surfactant to adsorb at the interface, relative to its tendency to form micelles.…”

“…The surface tension decreased as the concentration increased and reached a clear breakpoint, which was defined as the cmc. Table 1 summarizes the values of cmc, surface tension at the cmc γ cmc , surface excess concentration Γ , and area occupied per molecule A for 2C n Lac, which were obtained from the surface tension plots as well as the reported data for the corresponding conventional monomeric surfactants N-alkyllactobionamide C n MLA for n 10, 12, and 14 20 . Above the cmc, the surface tension for all the chain lengths continued to decrease slowly.…”

“…The deviation from the linearity for 2C n Lac suggested lower aggregation tendency, i.e., aggregates consisting of just 2-3 molecules, which were called premicellar aggregates, were formed below the cmc. We studied the adsorption and aggregation parameters such as pC 20 , cmc/C 20 ratio, ∆G°a ds , and ∆G°m ic . Table 1 lists the corresponding values for 2C n Lac and C n MLA.…”