The effect of electrolyte and temperature on adsorption properties of esterquats

Quaternary derivatives of lysosomotropic substances (QDLS) are compounds belonging to the group of esterquats which exhibit both surface properties as well as special biological activity. In view of the biological application of these types of esterquats and/or their mixtures, it is necessary to carry out research in the cellular environmental conditions. Living organisms constitute an environment rich in various electrolytes. In turn, the presence of an electrolyte strongly influences the surface properties of QDLS and their biological activity. Therefore, the aim of the study was to analyze the adsorption properties of quaternary ammonium bromides from the group of esterquats and their mixtures in air–electrolyte systems. The electrolytes studied were four different sodium salts, as their use would allow determination of the effect of anion of electrolyte on adsorption properties of substances investigated. The measurements were performed at two temperatures: 21 °C and 36.6 °C. The results obtained indicate that both, addition of salt and temperature rise led to improved surface activity and accelerated the adsorption process of QDLS at the air–electrolyte interface. However, the enhancement of adsorption properties observed is affected by the type of anion added as well as its concentration.