Interaction Between Multi-Walled Carbon Nanotubes And Bromime And Conducting Mechanism

In recent years, tremendous attention about the research of nano-materials has been focused on carbon nanotubes(CNT). Because of their unique physical, chemical and mechanical properties, CNT have a high value of science research and extensive potential of application in many fields, and are ideal filler of composites. As conductive dopant, It can enhance the electrical conductivity of composite to the level of dopant. But there are two main obstacles in the way of CNT 'application. One is the conductivity of CNT is not high enough, and the other is that due to the van der Walls forces, CNT can't dissolve in almost all solvents and homogeneous dispersions are not easily obtained ; and with the smooth surface, the interfacial bonding between CNT and matrix are very weak and the load can't transfer from the matrix to CNT effectively. To overcome these two challenges, some research works we did in these following issues are presented in the paper.1,.Bromine adsorbed on multi-walled carbon nanotubes(MWNT)Through adsorption of bromine vapor, the electrical conductivity of multi-walled carbon nanotubes (MWNT) can be enhanced by 3 times. Raman spectrum, UV-Vis spectra, IR, NIR and XPS spectra were used to characterize the material. The result indicates that there is conjugative effect between MWNT and bromine, which induces the change of electron distribution on the MWNT surface.2. Study on the reason why bromine can increase the conductivity of MWNT and on conducting mechanismThrough adsorption by bromine vapor, the electrical conductivity of multi-walled carbon nanotubes (MWNT) can be enhanced by 3 times. XPS, NIR spectrum, UV spectra, Raman spectrum indicated that there was conjugative effect between MWNT and bromine which induced the moving ofÏ€electrons from MWNT to bromine that increased the hole carrier density. According to the semiconductor energy bands, a microsystem model of br₂-adsorbed MWNT was assumed to interpret the interaction between bromine and MWNT and the conducting mechanism of bromine adsorbed MWNT.4. Dispersion improvement of Br-MWNT in polymer matrixBromine, as a dopant, was adsorbed onto MWNT to enhance the electrical conductivity of MWNT. MWNT were also modified by polystyrene. TEM and FESEM indicate that the modification of polystyrene improved the dispersion of Br-MWNT in polymer matrix while the electrical conductivity of Br-MWNT did not decrease.