Study On Chemical Modification And Ion Sensitive Of Multi-Wall Carbon Nanotubes

Since carbon nanotubes (CNTs) discovered, as a new one-dimension nanomaterial, CNTs have unique geometry structure and fantastic physical, chemical properties leading to many potential applications. Especially their electronic properties makes CNTs useful in researching and developing nano-device. CNTs always attractes attentions from worldwide several years, so become a leading edge problem in international nanomaterial research field. CNTs as sensor material, both here and abroad started correlation experiment, theoretical investigation and provided possibilites of practical application. In this paper, chemical modification for CNTs, CNTs films fundamental characteristics and ion sensitive characteristics were proceed experiment and theoretical investigation.The function modification of carbon nanotubes has been obtained by mixed acid and thionyl chloride treatment, spectral analysis present a contrast between treated CNTs and untreated ones. The resistance model of CNTs films was introduced through heterogeneous fibrillar film resistance model, the resistance of films consists of the resistance of CNTs junctions and CNTs tube resistance. CNTs junctions resistance is positive exponentially proportional to temperature and proportional to the distance between CNTs tubes. CNTs tube resistance is negative exponentially proportional to temperature. Chemical modification makes CNTs shorter, opening cap and increaseing greatly number of CNTs junctions, as a result, increases the resistance of CNTs films, so the resistance of treated CNTs films is decided by CNTs junctions resistance.The resistance-temperature relation of CNTs films is different between treated and untreated ones, the resistance of untreated ones is mostly decided by CNTs tube resistance, is metallicity. The resistance of treated ones is mostly decided by CNTs junction resistance, temperature coefficient is negative, is semiconductor. Moreover, the resistance relative variance increase with increasing modification hours.After researching humid sensitive effect of MWNTs films, we find that the untreated CNTs films surface don't contain hydroxyl group and isn't sensitive to humidity.Treated CNTs films contain a large number defects and many active function groups, absorption is very high, is sensitive to humidity. Moreover, it's sensitivity increase with increasing modification hours.A potential generated directly by the ion vapor over CNTs films, this potential increase with increasing effective distance and vapor velocity. The chemial modification...