Solvent polymeric membranes based on quaternary ammonium salt tridodecylmethylammonium chloride (TDDMACl) with different concentration were investigated. Potentiometric measurements confirmed the deviation of selectivity of the membranes with low TDDMACl concentration from Hofmeister lipophilicity series likely caused by pH-dependence of response. Electrochemical impedance spectroscopy (EIS) was applied to study conductivity and to determine energetic parameters of conductivity (activation energy and pre-exponential factor) for the first time for this type of materials. The dissociation degree and association constants of TDDMACl in the membrane as well as membrane relative permittivities were calculated on the basis of EIS data.