Welzel Petra B, Rauwolf Cordula, Yudin Olexandr, Grundke Karina
Institute of Polymer Research Dresden e.V. Hohe Strasse 6, Dresden, D-01069, Germany.
J Colloid Interface Sci. 2002 Jul 1;251(1):101-8. doi: 10.1006/jcis.2002.8356.
The interaction of inorganic ions with low-energy hydrophobic surfaces was examined using model systems of solid polymers without ionizable functional surface groups in aqueous electrolyte solutions. Low-rate dynamic contact angle measurements with captive bubbles in conjunction with axisymmetric drop shape analysis (ADSA) were performed to study the influence of electrolyte ions (in the aqueous test solutions) on the wettability of the polymers. When various types of ions were used, no significant change in advancing and receding contact angles was observed. The contact angle hysteresis was small. The zeta potential of the model polymers in aqueous electrolyte solutions was determined from streaming potential measurements. The variation of the zeta potential at different pH levels indicates preferential adsorption of hydroxyl ions at this interface. However, the presence of electrolytes at the interface between water and the different model polymers did not influence the macroscopic contact angle. The results may suggest the absence of any specific interaction between the ions and the solid polymer, as this should result in changes of hydrophobicity. Similar to the air/water interface, the composition and the potential of the polymer/water interface are obviously determined predominantly by the aqueous phase with only slight influence from the solid phase.
在水性电解质溶液中，使用不含可电离功能性表面基团的固体聚合物模型系统，研究了无机离子与低能疏水表面的相互作用。采用俘获气泡的低速率动态接触角测量结合轴对称滴形分析（ADSA），来研究（水性测试溶液中的）电解质离子对聚合物润湿性的影响。当使用各种类型的离子时，前进接触角和后退接触角均未观察到显著变化。接触角滞后现象较小。通过流动电势测量确定了模型聚合物在水性电解质溶液中的ζ电位。不同pH水平下ζ电位的变化表明，在该界面处优先吸附了氢氧根离子。然而，水与不同模型聚合物之间的界面处存在电解质，并未影响宏观接触角。结果可能表明离子与固体聚合物之间不存在任何特异性相互作用，因为这会导致疏水性发生变化。与空气/水界面类似，聚合物/水界面的组成和电位显然主要由水相决定，固相的影响很小。
