Surface and Antimicrobial Activity of Sulfobetaines

Abstract Sulfobetaines belong to the group of zwitterionic surfactants. They are electroneutral salts, which have in the same molecule, two ionic centers with different charge. Due to the specific structure they exhibit excellent properties such as good solubility in water and detergency. In this paper we present surface properties and adsorption parameters of sulfobetaines in water/air systems. From the adsorption isotherms the CMC value, the surface tension and surface pressure at the CMC as well as the efficiency of adsorption were determined. Physicochemical analyses of the data allowed for the further description of adsorption process. Results showed that sulfobetaines exhibit good surface properties especially low CMC and p20 values. Additionally the antimicrobial activity of sulfobetaines solutions against gram‐positive and gram‐negative bacteria were tested by the well‐diffusion method. MIC values and growth kinetics were determined by microdilution method. Antimicrobial assays demonstrated that sulfobetaines can be good antibacterial agents, but the activity of surfactants strongly depends on alkyl chain length.