Adsorption behavior and wettability by Gemini surfactants with ester bond at polymer-solution-air systems

The wettability of Gemini surfactants with ester bond at Polytetrafluoroethylene (PTFE) and Paraffin surfaces have been investigated and the different physicochemical parameters such as surface tension (γLV), contact angle (θ), spreading coefficient (S), adhesional tension (γLVcosθ) and work of adhesion (WA) have been estimated. The obtained results indicate that the surface tension and contact angle decrease with the increase of surfactant concentration, and they tend to be stable when the concentration is more than CMC. The wettability of m-6-m on PTFE and Paraffin surfaces is better than that of m-2-m. A linear relationship exists between the adhesional and surface tension during a range of certain concentrations, the absorption amount of the surfactant at the liquid-air interface is larger than that at the PTFE-liquid interface. Meanwhile, this linear relationship is only applicable for 12-2-12 and 14-2-14 in the case of Paraffin. The adhesional tension increases with the increase of concentration, and it keeps constant when the saturated adsorption film has been formed at both liquid-air and solid-liquid interfaces. The better wettability of Gemini surfactants with ester bond on PTFE and Paraffin has the better adhesion.