Surface activity and cleaning performance of Gemini surfactants with rosin groups

Novel rosin-based Gemini surfactants (RGS-n) are synthesized from dehydroabietylamine and four different N, N-dimethyl long-chain aliphatic amines. Compared with traditional surfactants, the critical micelle concentration (CMC) of RGS-n is reduced by 2 to 3 orders of magnitude. The three-ring skeleton of dehydrogenated rosin can improve the emulsification of RGS-n. Besides, the Kraff points of RGS-n are less than 0 °C, indicating the availability of RGS-n at low temperature. RGS-n exhibits a better cleaning effect through the combination of electrostatic interaction with carboxyl groups of rosin and the emulsification of RGS-n. The smaller presence of residual rosin on printed circuit boards (PCBs) after cleaning with RGS-n indicates higher cleaning performance of RGS-n. The effect of the length of the hydrophobic chain on cleaning efficacy is analyzed for PCBs. Higher cleaning efficacy is observed at RGS-14. This work has specific research significance for Gemini surfactant application as a cleaning agent in industrial circuit board cleaning.