ABSTRACT
The surface tension γ of any pure liquid will change when another substance is dissolved. The change in γ will cccand the characteristics of the solute added. Surfactants dissolve in water and give rise to low surface tension of the solution. The surface tension data in the case of a homologous series of alcohols and acids show some simple relation to the alkyl chain length. The effect of chain length on surface tension arises from the fact that as the hydrophobicity increases with each –CH2– group, the amphiphile molecule adsorbs more at the surface. The magnitude of the surface tension is reduced since the hydrophobic is energetically more attracted to the surface than being surrounded by water molecules inside the bulk aqueous phase. The solubility of all ionic surfactants is low at low temperature but at a specific temperature the solubility suddenly increases.
