ORIGINAL ARTICLE Novel Ester-linked Anionic Gemini Surfactant: Synthesis, Surface-Active Properties and Antimicrobial Study Manisha B. Ahire 1 • Sunil S. Bhagwat 1 Received: 11 February 2017 / Accepted: 15 May 2017 Ó AOCS 2017 Abstract A novel anionic gemini surfactant containing an ester bond in the spacer group was synthesized using car- danol as the raw material and characterized by IR, 1 H NMR and 13 C NMR. The surface properties of the gemini sur- factant were investigated and compared with its corre- sponding single chain surfactant counterpart. It was found that this novel gemini surfactant exhibited a low critical micelle concentration value (1.9 mM) and good efficiency in reducing surface tension of water (33.6 mN/m). The gemini surfactant was found to have antimicrobial activity against Gram-negative (Escherichia coli and Pseudomonas aeruginosa), Gram-positive (Bacillus subtilis and Staphy- lococcus aureus) bacteria and fungi (Aspergillus niger, Aspergillus flavus, Candida albicans and Rhizopus stolo- nifer). The gemini as well as the corresponding single chain surfactant showed good antimicrobial activity against all pathogenic microorganisms studied and can be employed as an antimicrobial agent. The synthesized novel anionic gemini surfactant possesses an excellent wettability and low foamability. Keywords Anionic gemini surfactant Á Synthesis Á Cardanol Á Critical micelle concentration Á Wetting agent Á Antimicrobial activity Abbreviations CMC Critical micelle concentration (mM) CSMS Cardanol sulfonate monomeric surfactant CSGS Cardanol sulfonate gemini surfactant SDBS Sodium dodecyl benzene sulphonic acid CTAB Cetyl trimethyl ammonium bromide TLC Thin layer chromatography 13 C NMR Carbon nuclear magnetic resonance 1 H NMR Proton nuclear magnetic resonance D 2 O Deuterated water DMSO-d 6 Hexadeuterated dimethyl sulfoxide CDCl 3 Deuterated chloroform IR Infrared spectrometry GC–MS Gas chromatography mass spectroscopy List of symbols c Surface tension (mN/m) cCMC Surface tension at CMC (mN/m) C max Maximum surface excess concentration (mol/cm 2 ) A min Minimum surface area per molecule (nm 2 ) C 20 Concentration of surfactant required to reduce surface tension by 20 mN/m k max Wavelength maximum (nm) b cb Counterion binding coefficient a cb Counterion dissociation coefficient h Contact angle (°) R Universal gas constant T Absolute temperature N A Avogadro’s number (6.022 9 10 23 mol -1 ) Electronic supplementary material The online version of this article (doi:10.1007/s11743-017-1977-1) contains supplementary material, which is available to authorized users. & Sunil S. Bhagwat ss.bhagwat@ictmumbai.edu.in 1 Department of Chemical Engineering, Institute of Chemical Technology, Matunga, Mumbai 400 019, India 123 J Surfact Deterg DOI 10.1007/s11743-017-1977-1