UBC Undergraduate Research

Investigation of surfactant surface tension and its correlation with temperature and concentration Cheng, Li Yaw (Michael); Wei, Su Min (Lisa)


Surface tension is a property that defines the energy per unit area of a liquid-gas interface. The purpose of this study is to investigate the surface properties and the process of aggregation of surfactant micelles in detergents. By using a drop-weight method, the surface tension of detergent solutions was determined under standard pressure condition 1 bar. A 100% concentrated detergent solution was subject to heating. Data analysis showed that surface tension decreased linearly with increasing temperature, as represented by the equation ƴ = – 0.1766 mN/(m⋅K)(x) + 94.654 mN/m, where x is temperature. When subjected to variations in concentration, surface tension of the detergent decreased until reaching the critical micelle concentration, as modelled by the segmented linear regression ƴ = – 0.565 mN/(m⋅%)(x) + 61.7 mN/m when x < 50%, and ƴ = 33.45 mN/m when x ≥ 50%, where x is concentration.

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Attribution-NonCommercial-NoDerivatives 4.0 International