ИСТИНА

It is known that track membranes could be used as template matrixes for so-called matrix synthesis of nanowires (NWs) [1, 2]. The characteristics of obtained NWs – geometrical parameters, structure and so on- depend on matrix parameters and electrodeposition features. Among other parameters, the stability of NWs is rather important (both from theoretical point of view and for practical applications). For example, the degradation of ensembles of copper (or silver) NWs during electron emission or ion emission experiments is the main origin of instability of emission process [3, 4]. It is safe to say that stability of these nanostructures are differ from stability of bulk material. In addition, it is obviously that this parameter of NWs is not investigated at all. In this work, the first results for thermal, chemical and radiation stability of NWs were obtained. Copper NWs with different diameters (50-500 nm) were electrochemically grown using PET track membrane. Stability of copper NWs was controlled by SEM and in some experiments-additionally by TGA (Thermogravimetric analysis) and X-ray analysis. Thermal stability was tested in vacuum and it was found that melting and bending temperature for NWs is 20-50oC lower than for bulk copper; this effect depends on wire` diameter. Annealing in air condition leads to fast oxidation, which starts at rather low temperatures 350° ÷ 400o C (for diameter 100 nm). Dependence of stability on annealing temperature and NWs parameters was investigated. Chemical stability of Cu NWs was also tested - it was found that even the NWs with diameter 60 nm are rather stable in alkali solutions: visible lenght changing were detected only after 3 hours in 10 N NaOH at t = 70o C. NWs with bigger diameter demonstrated higher resistance. At the same time acid - stability test (3% HCl, room temperature) demonstrated low resistance to acid: samples were totally destructed after 3-5 hours of etching. The radiation stability of NWs was also studied. The dependence of stability on diameter and other parameters of NWs was found and discussed.