Density and viscosity of α-amino acids in aqueous solutions of cetyltrimethylammonium bromide

Abstract

The densities and viscosities of aqueous solution of cetyltrimethylammonium bromide (0.01 mol kg−1) (CTAB) and solutions of CTAB containing amino acids, viz., glycine, l-serine, and l-valine (0.01–0.05 mol kg−1), were determined in the temperature range 298.15—313.15 K. Apparent molar volumes of the amino acids were calculated from the density and viscosity values. The calculated apparent molar volumes were used to calculate standard partial molar volumes (-V20) and standard partial molar volumes of transfer of amino acids from water to an aqueous solution of CTAB. The viscosity values were used for the calculation of the viscosity coefficients A and B in the Jones—Dole equation. The linear dependences of -V20 and B on the number of carbon atoms in the alkyl chains of the amino acids were found. The results obtained were used in analysis of hydrophilic-hydrophilic, hydrophilic-hydrophobic, and hydrophobic-hydrophobic interactions that occur during dissolution of amino acids in an aqueous solution of CTAB.