The mass transfer performance is usually affected by the wetting of the packing surface with absorbent solution, and the wetted surface can be affected by interfacial disturbances resulting from the gradient in surface tension between water vapor and absorbent solution. In order to discuss the effects of interfacial phenomena on mass transfer performance of water vapor absorbed by triethylene glycol (TEG) and lithium bromide (LiBr) solutions, an absorber packed closely with cylindrical packing was designed in this study and the packing material was polyvinyl chloride. In addition, the interfacial behaviors were observed from water droplet positioned on the surface of absorbent solution, and the surface stress was defined and calculated to analyze how mass transfer performance was affected by the stress. Experimental results show that surface stress increases with increases in concentration of TEG solution. The surface stress increases significantly when the concentration of TEG solution exceeds 92 wt.% The area of packing wetted by TEG solution increases as the concentration of TEG solution and humidity increase. Therefore, the mass transfer performance also increases with the higher concentration and higher humidity. (C) 2013 Elsevier B.V. All rights reserved.