Surface tension, foamability and aggregation properties of amino acid surfactants (AAss) solutions (pure and mixed with n-octanol)

Data on equilibrium surface tension (SFT), foamability (foam column parameters) and DLS measurements performed in solutions of three amino acid surfactants (AASs) with different hydrophilic heads (amino acid), namely: N-lauroyl-L-alanine (C12-ALA), N-lauroyl-L-leucine (C12-LEU) and N-lauroyl-L phenylalanine (C12-PHE). Pure AASs solution of various concentrations as well their mixtures with constant concentrations of n-octanol (simple fatty alcohol - C₈OH) were studied. These studies were aimed to investigate the synergistic/antagonistic effects occurring in mixed solutions of AASs with non-ionic additive.

• The equilibrium values of the surface tension for all tested systems (either pure or blended AASs/C₈OH solutions) were determined using the bubble shape method in the PAT-1 tensiometer (SINTERFACE Technologies, Berlin, Germany).
• Foamability and foam stability of the pure AASs solutions of various concentrations, as well as their blends with constant C₈OH amount were assessed using a Dynamic Foam Analyzer (DFA100, KRÜSS GmbH) apparatus.
• Aggregation dynamics and aggregates’ hydrodynamic radii in blend AASs/ C₈OH solutions) were monitored by the Dynamic Light Scattering (DLS) method in the Zetasizer ZS Malvern ZEN 3500 apparatus (with a laser of a wavelength 532 nm).