Development of High-resolution Mobility System and Structural Control of Nanocarbon Materials.

点击翻译按钮获取中文摘要

The Ion Mobility System has been utilized to analyze structures of aerosol particles or those of clusters. This measurement system provides lots of advantages to clarify the new structures but has not been applied to observe "long-term changes", which is crucial for the applications of nanocarbon materials. In this research project, we have succeeded to develop a new type ion mobility system achieving long term observation for more than two hours.The system consists of stacked ring electrodes where an RF electric field (600Vpp, 20kHz) for the particle trap and an LF filed (9Vpp, 2.5Hz) for the mobility measurement were applied. This system utilizes the two ion traps in ambient condition, which is novel feature of the systems. With this system charged particles were observed for more than two hours. The particles (diameter=10um and m/z=2×10^8) were produced from NaCl water solution with concentration from 5 to 27wt. % (saturated solution) by an atomizer where 10kV was applied. The parti … More cles were trapped and were analyzed with up-down movements induced by LF filed. The trapped particles were irradiated by a laser and were monitored by a digital camera. The particle size were analyzed by the amplitude of the movement induced by the LF field since the larger the particle size is the smaller the mobility and the amplitude are.The particles in the system gradually changed its size in the time scale of hours through absorbing water vapor from the air and vaporization of water of the particles. The trend of the particle size change strongly depends on the concentration of the NaCl, which clarified that the system can analyze long-term evolution such as growth processes of nanocarbon materials sensitively.These results show the potential of the system, which will be enhanced by the newly developed larger system. The newly developed system can hold and move particles with a 500mm long trap. This system has much higher resolution and can determine the particle size and the amount of charges precisely with the hybrid monitoring of the long movement induced by the applied electric field and free fall movement induced by the gravity. The system is also equipped an ion funnel which enhances the transfer of the ion from the source of the particle and to other measurement system such as mass spectrometer. With the high resolution and sensitivity, we are ready to monitor and control of nanocarbon materials. Less