Surface thermodynamics of DMA2P, DMA2P-MEA and DMA2P-PZ aqueous solutions

The surface tension (γ) of 1-dimethylamino-2-propanol (DMA2P), DMA2P-monoethanolamine (MEA), and DMA2P-piperazine (PZ) aqueous solutions was measured by using the BZY-1 surface tension meter. The temperature ranged from 303.2 K to 323.2 K. The mass fractions of DMA2P, MEA and PZ respectively ranged from 0.30 to 0.50, 0.05 to 0.15 and 0.025 to 0.075. An equation was proposed to model the surface tension and the calculated results agreed well with the experiments. The surface thermodynamics including surface enthalpy and surface entropy were determined and their concentration dependence was analysed.