Synergistic Effect and Phase Behavior of SCG-CAPB-H2O Ternary Compound System

Abstract

The physical properties of sodium cocoyl glycinate (SCG) and the synergistic effects within the SCG/CAPB complex system were investigated using visible–ultraviolet spectrophotometry and a surface tension meter. Analysis of the synergistic parameters of the complex system revealed that the combination of SCG and cocamidopropyl betaine (CAPB) yielded superior results compared to the individual use of SCG. Building upon this, the ternary phase behavior of the SCG/CAPB/H2O system was further explored. Different lyotropic liquid crystal phases were identified using polarized optical microscopy (POM) and small-angle X-ray scattering (SAXS). Surfactant solutions with varying mass fractions exhibited diverse phase behaviors, including the micellar phase (L1), micelle–solid mixed phase (L1-S), hexagonal phase (H), and lamellar phase (Lα), with the insoluble solid phase predominating. The investigation of the ternary phase diagram of SCG/CAPB/H2O provided valuable guidance for detergent formulation screening, enriched the understanding of sodium cocoyl glycinate complex systems, and further promoted the utilization of amino acid-based surfactants in the field of personal care products.