Carbon Nanotube / Teflon Composite Field Emission Properties

As a new kind of nanomaterial, carbon nanotube (CNT) has been widely attended and studied by many scientists from the beginning since it was discovered because of its unique physical and chemical performance and its application foreground. Thanks to the excellent field-emission property, CNT and its composites have tremendous application potential in the area of field-emission vacuum devices, especially panel display.Because field-emission devices have strict requirement for the vacuum environment, the vacuum performance of the field-emission cathode was very significant. In this thesis, carbon nanotubes/polytetrafluoroethylene (CNTs/PTFE) composite materials for field-emission cathode were prepared, its field-emission property and the predominance of the application in field-emission devices were studied. The main contents in this paper were as follows:1. CNTs were synthesized by chemical vapor deposition (CVD) method, the mechanism of CNTs growth was analyzed. Then the methods of acidic H2O2 solution disposal and air oxidation were used to purify CNTs. Experimental parameter was optimized in synthesizing CNTs process and the temperature and time for the air oxidation were ascertained.2. CNTs/PTFE composite materials were prepared by using physical mixing method, purified CNTs and PTFE latex were as original materials. The influence for the field-emission property of CNTs/PTFE composite material with different mass content of CNTs were discussed and optimal CNTs mass content were ascertained. It was proved that by using the method of surface score for CNTs/PTFE cathode, the field-emission property was improved.3. To study the influence of the field-emission cathode materials for the vacuum environment of the field-emission devices, ambipolar electrode configuration was designed in this paper. CNTs/PTFE and CNTs/epoxy composite materials were used as field-emission cathode and the two electrode configurations were encapsuled into a static vacuum system respectively. By contrastive testing, the field-emission properties...