New cationic ionic liquid surfactants (ILS) based on (C9-C10, C12 and C14) alkyl bromides and N-2-hydroxypropyl piperidine have been synthesized. Colloidal parameters of aqueous solutions of the obtained ILSs were studied by surface tension and dynamic light scattering methods. Specific electrical conductivity was measured by the conductometric method. Depending on the alkyl chain length, critical micelle concentration (CMC), maximum adsorption (Гmax), the minimum cross-sectional area of the surfactant polar group (Amin), adsorption efficiency (pC20), surface pressure (πCMC), degree of counterion binding (β), changes of the Gibbs free energy of micellization and adsorption (ΔGmic and ΔGad) were studied. The ILSs antimicrobial properties were tested on various bacteria and fungi. © 2021 Elsevier B.V.