化学刻蚀制备亲水性铝及润湿性变化规律

Hydrophilic Aluminum Prepared by Chemical Etching and Its Wettability Change Rule

目的通过化学刻蚀的方法制备具有亲水性的纯铝与高纯铝表面,在室温下进行时效,分析润湿性随时效时间的变化规律。方法实验以2 mol/L浓度的盐酸进行刻蚀,将试样分别刻蚀4、8、12、16、20 min,吹干制备好的试样。利用OCA15EC接触角测量仪测定润湿角,将试样放置在室温下进行时效,并记录时效后的润湿角,分析润湿角变化的规律;采用场发射扫描电子显微镜观察试样表面的微观形貌,结合Wenzel理论与Cassie理论分析润湿角变化的原因;对试样进行EDS分析,分析时效后试样所含元素含量的变化情况,阐述润湿性变化的机理。结果不同刻蚀时间制备的样品润湿角存在差异,经过室温时效,润湿角呈现增大的趋势。结论纯铝在刻蚀时间16 min时能够获得超亲水的表面,在室温下时效5天能维持润湿角在20°以下。高纯铝在刻蚀时间为12 min时能够获得超亲水表面,经过5天的室温时效,12 min刻蚀的样品润湿性保持得较为稳定,润湿角维持在12°以下,其他刻蚀时间的样品亲水性及稳定性略差。

The work aims to prepare hydrophilic aluminum and high purity aluminum surface by chemical etching, perform aging at room temperature and analyze change rule of wettability with aging time. The samples were etched by 2 mol/L hydrochloric acid, and the samples were etched for 4 min, 8 min, 12 min, 16 min and 20 min respectively and then blow-dried. OCA15EC contact angle meter was used to measure wetting angle and the sample was placed at room temperature for ageing. The wetting angle after ageing was recorded and the change rule of wetting angle was analyzed. Morphology of the sample surface was observed under field emission scanning electron microscopy. Causes of wetting angle change were analyzed by combining Wenzel theory and Cassie theory; EDS analysis was performed to the sample, content change of elements contained in the samples after aging was analyzed, and the change mechanism of wettability was elaborated. Wetting angle of the samples prepared in different etching time was different, and wetting angle of the samples was increased by room temperature ageing. A super-hydrophilic surface can be obtained from the pure aluminum after 16 min of etching, and the wetting angle can be maintained at 20° or less after 5 days of room temperature ageing. A super-hydrophilic surface can be obtained from the high purity aluminum after 12 min of etching, and the wetting angle can be maintained at 12° or less after 5 days of room temperature ageing. Samples being etched for other durations were slightly less hydrophilic and stable.