In this study, the authors investigated the wettability change of atmospheric-pressure-cold-plasma (APCP)-treated polytetrafluoroethylene (PTFE) surfaces with time under different storage temperatures and pressures, and the results indicate that low temperature can hinder wettability recovery. After storage for 5 days, the water contact angle (WCA) of PTFE stored at room temperature (25°C) recovered from 19 ± 2 to 54 ± 2°, while the WCA of PTFE stored at low temperature (−10°C) increased to just 42 ± 3°. Then, the mechanism contributing to the slower wettability recovery was investigated by analyzing surface chemical compositions through X-ray photoelectron spectroscopy and observing surface morphologies using atomic force microscopy. After 15-day storage, the oxygen (O) and nitrogen (N) contents decreased obviously, while the fluorine (F) content increased. The fluorine content of the sample stored at low temperature was 20% less than that of the sample stored at room temperature. In contrast, surface micromorphologies were unchanged during storage, and the surface roughness R _a of each sample was around 7 nm. Finally, peel strength tests were conducted on APCP-treated PTFE surfaces stored at different temperatures, and the surfaces stored at low temperature maintained better adhesive properties. After 15 days of storage, the adhesive strength could still reach 400 N/m, which was 376% higher than that of the untreated surface. The research results are expected to facilitate practical applications of APCP modification and PTFE surfaces significantly.

中文翻译：

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等离子体的稳定性改善了聚四氟乙烯表面的粘合性能

在这项研究中，作者研究了常压冷等离子体（APCP）处理的聚四氟乙烯（PTFE）表面在不同储存温度和压力下随时间的润湿性变化，结果表明低温会阻碍润湿性恢复。储存5天后，室温（25℃）储存的PTFE的水接触角（WCA）从19±2恢复到54±2°，而低温（-10℃）储存的PTFE的水接触角（WCA）增加至仅 42 ± 3°。然后，通过 X 射线光电子能谱分析表面化学成分并使用原子力显微镜观察表面形貌，研究了润湿性恢复较慢的机制。存放15天后，氧（O）和氮（N）含量明显下降，而氟（F）含量增加。低温保存的样品氟含量比室温保存的样品低20%。相比之下，在储存过程中表面微观形貌没有变化，每个样品的表面粗糙度R _a约为7 nm。最后对经过APCP处理的PTFE表面在不同温度下储存进行了剥离强度测试，低温储存的表面保持了较好的粘合性能。存放15天后，粘合强度仍可达到400 N/m，比未处理表面提高376%。研究成果有望显着促进APCP改性和PTFE表面的实际应用。