Synthesis,Surface Activity,and Antimicrobial Efficacy of Hydrogenated Cardanol-Derived Positively Charged Asymmetric Gemini Surfactants

Nine different hydrogenated cardanol-based quaternary ammonium compounds including one conventional single-tale single-head surfactant, one bicephalic single-tale double-head surfactant, and seven asymmetric Gemini surfactants were synthetized using a simple process with high yields. Their structures were characterized using ¹H NMR, ¹³C NMR, and high-resolution mass spectral studies. Their surface active properties were evaluated by the wilhelmy plate method at 25 °C and physical parameters like CMC, γ_CMC, π_CMC, C₂₀, τ_CMC, and A_min were calculated. The Krafft temperature values of C-BP-1, C-BP-4, and C-BP-6 are lower than 0 °C, suggesting high-potential industrial application. All synthesized compounds but C-BP-F exhibit great antimicrobial ability against Gram-positive bacteria (S. aureus ATCC 25923] and C. glutamicum ATCC 13032]) while inadequate antimicrobial ability against Gram negative strains (E. coli ATCC 25922] and P. aeruginosa ATCC 27853]).