憎水膜层在大气暴露和模拟积水环境中的失效行为研究

Deterioration Process of Hydrophobic Films Exposed in Atmosphere and Simulated Condensation Water

研究憎水膜层表面憎水角、憎水角滞后、红外吸收光谱、交流阻抗响应、表面微观结构等变化,探讨不同环境条件和基材对憎水膜层失效行为的影响。结果表明:室外大气暴露环境中憎水性能衰减速率较室内环境的快,室内环境暴露115d的膜层憎水角仍在100°以上,而同样在室外环境中憎水膜层的憎水角则下降到50°左右。红外分析表明,室外憎水膜层中Si—O—Si长链结构和Si—H键遭破坏;在模拟积水环境中钢与铝合金上的膜层憎水性能及水滴在膜层表面的流动性能差异较大,但两种材料上的憎水膜层分子结构未发生明显改变;AFM测试结果表明,膜层本身粗糙度的降低是导致憎水性能下降的原因之一。

The influence of different environments and substrates on the failure of hydrophobic films was studied by analyzing the variations of contact angle, contact angle hysteresis, FTIR spectra, EIS and surface mierostructure. The results reveal that water-repellent performance of hydrophobic films exposed in outdoor decreases much faster than that in indoor films, whose contact angles are still above 100° after 115 days exposure, while films＇ contact angles are only about 50° in the environment of outdoor. The results of FTIR spectra indicate that long chain structure of the Si-O-Si and Si-H bond of hydrophobic films are destroyed in outdoor. Furthermore, properties of the water-repellent and the flowing of hydrophobie films based in carbon steel and aluminum alloy substrate in simulated condensation water show different trends apparently, however the molecule structure of both do not change evidently. According to the AFM results, one of the reasons that cause the decline of water-re- pellent performance is the diminution of the roughness of hydrophobie films themselves in simulated eondensation water.