Visual and real-time detection of the critical micelle concentration of nonionic surfactants using a supramolecular...

The critical micelle concentration (CMC) is considered one of the important parameters for evaluating and comparing surfactants. We have developed a novel method for detecting the CMC of nonionic surfactants, based on the environmentally responsive characteristics of cyanine dyes probes. Notably, this method exhibits high sensitivity, visual real-time monitoring capabilities, and robust anti-interference properties. The method remains effective even under alterations in pH (2-12), metal ion concentrations (0-150 mM of K⁺, Na⁺, Ca²⁺) and salinity levels (0-20 g/L). Furthermore, the method has been successfully applied to the analysis of real water such as lake water, water flooding, and oil-field sewage containing polymers, demonstrating its good applicability. This marks the first instance where we establish the application of detecting the CMC of nonionic surfactants using cyanine dye probes, offering a fresh perspective for developing highly sensitive, visual, real-time, and interference-resistant CMC detection methodologies.