低能Ar离子束处理对CuO纳米线的微观结构、化学成分及润湿性能的影响

离子束技术作为一种精确可控的表面改性技术，已开始成为调控纳米材料结构和性能的重要技术之一。利用热氧化法在铜网表面直接合成高密度、高质量和高长径比的CuO纳米线(CuO NWs)阵列，采用扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱(XPS)和接触角测试仪，研究低能(860 eV)Ar离子束表面处理不同时间(0、5、10、15、20 min)对CuO NWs微观结构、化学成分及润湿性能的影响。结果表明：CuO NWs表面经低能Ar离子束处理后，CuO NWs顶端弯曲，表面变粗糙。随处理时间的增加，相邻CuO NWs之间出现熔合现象，CuO NWs顶端逐渐由双晶结构转变为非晶结构，CuO NWs表面部分CuO逐渐被还原成Cu₂O,CuO NWs表面的静态水接触角(SWCA)值从(86±2)°先大幅度增大到(152±3)°后轻微减小到(141±2)°，当处理时间为10 min时，获得最大的SWCA值为(152±3)°，表明CuO NWs表面具备超疏水性。因此，利用低能Ar离子束表面改性技术可以基本实现对CuO NWs形貌、结构和性能等的精确调控。研究结果可为...

Effects of Low-energy Ar Ion Beam Treatment on Microstructure, Chemical Composition, and Surface Wettability of CuO Nanowires

Recently, cupric oxide nanowires(CuO NWs) have drawn considerable attention owing to their unique properties and potential technical applications, which are mainly derived from their small size and particular structure. In practical applications, many methods have been employed to tailor the structure and composition of CuO NWs, and hence improve their performance. Among these, ion beam technology, as a precise and controllable surface decoration technique, has attracted increasing research interest for modulating the properties of CuO NWs. First, highly crystalline CuO NWs with high density and large aspect ratio were prepared via thermal oxidation of a copper mesh in an oxygen atmosphere. Subsequently, the CuO NWs were bombarded with an Ar ion beam for different durations (0, 5, 10, 15, and 20 min) at the energy of 860 eV. The effects of low-energy Ar ion beam treatment on the microstructure, chemical composition, and surface wettability of the CuO NWs were investigated via scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), transmission electron microscopy(TEM), and contact angle measurement (CA). The results show that the tips of the CuO NWs became bent, and the surfaces of the CuO NWs were rougher after the low-energy Ar ion beam treatment. The bending of the CuO NWs may be due to the thermal stress generated by the temperature gradient, caused by heat from the incident Ar ions. The surface roughness of the CuO NWs was attributed to the surface sputtering effect. With an increase in treatment time, high-temperature fusion appeared between the adjacent CuO NWs because excessive energy precipitation cannot diffuse in a short time. With longer treatment times, the tip areas of the CuO NWs gradually changed from a bicrystalline(monoclinic) to an amorphous structure. This structural change was due to the formation of crystal defects, such as vacancies, from the surface sputtering effect, as well as the diffusion of defects into the inner CuO NWs induced by the temperature-rising effect. In addition, some of the CuO on the surface of the CuO NWs was reduced to Cu₂O after the ion beam treatment. This is closely related to the preferential sputtering of oxygen in the metal oxide, and the vacancy-mediated diffusion of copper atoms to the surface may also play a role in the formation of Cu₂O. Furthermore, measurements showed that the static water contact angle(SWCA) of the CuO NWs dramatically increased from (86±2)° to (152±3)°, and then slightly decreased to (141±2)° after treatment for different times. The largest SWCA approached (152±3)° with the optimal treatment time of 10 min, suggesting that the surface of CuO NWs is super-hydrophobic. The shift in the surface wettability of the CuO NWs can be attributed to the special rough structure created by modification with the low-energy Ar ion beam, which enables the surface of the CuO NWs to trap a large amount of air, efficiently avoiding direct contact between the water droplets and CuO NWs. Therefore, low-energy Ar ion beam surface treatment is a promising technique for achieving more precise modulation of the morphology, structure, chemical composition, and properties of CuO NWs. The results of this study also provide a theoretical and experimental basis for accurately regulating the properties of other one-dimensional nanomaterials using ion beam technology.