Controllable Preparation And Asymmetric Functionalization Of Multi-Walled Carbon Nanotubes

Because of its unique structure, excellent electrical, mechanical, optical and thermal properties, carbon nanotubes are used in a wide range of applications, such as composite materials, optoelectronic materials, biological and chemical sensors, new energy battery and field emission devices, which have attracted considerable attention of many scholars from physics, chemistry, materials, biology and other disciplines. Aligned multi-walled carbon nanotubes exhibit some special features, owing to its large specific surface areas, high purity carbon, excellent conductivity, uniform length and orderly array, which are not available in disordered carbon nanotubes. However, its surface characteristics limit the range of applications. So functionalizing aligned multi-walled carbon nanotubes can improve surface activity and provide scientific value for expanding the basic research and application development of aligned multi-walled carbon nanotubes.In this paper, the controllable preparation of multi-walled carbon nanotubes was carried out to synthesize of amphiphilic carbon nanotube arrays. We systematically studied the controllable preparation technologies of multi-walled carbon nanotubes and the synthesis method of amphiphilic multi-walled carbon nanotubes. The main works are as follows:(1) Three different structures of carbon materials (carbon spheres, bamboo-like carbon nanotubes, straight carbon nanotubes) were synthesized by pyrolysis of iron(II) phthalocyanine under different flow rates of H2with the method of atmospheric pressure chemical vapor deposition (APCVD) at1000℃. The morphologies and structures of carbon materials were characterized by SEM, TEM and Raman. Combined with the experimental results, we discussed in detail the three forming proceses of carbon micro/nano-structural materials and the inner link of nanomaterials. In the end, The formation mechanism of carbon nanotubes was properly proposed, which enriches growth mechanism theory of carbon nanotubes and has good significance for mass-producing low-cost carbon nanotubes.(2) Aligned multi-walled carbon nanotubes (AMWCNTs) were synthesized by pyrolysis of iron(II) phthalocyanine with the method of APCVD at900℃. The morphologies and structures of the carbon materials were characterized by SEM, TEM and Raman. During the experiment, the effect of carbon dosages and reaction temperatures on synthesis of AMWCNTs was discussed. we explored the optimal conditions to produce AMWCNTs with regular arrays and different lengths.(3) The amphiphilic multi-wall carbon nanotubes were fabricated by three steps, including dedoping AMWCNTs; protection of AMWCNTs coating and reversal; followed by grafting hydrophobic and hydrophilic groups. It was illustrated by FT-IR, the EDX element mapping spectrum and contact angle test and scattering that the amphiphilic multi-wall carbon nanotubes was successfully prepared, showing the construction of multi-functional nano-equipments and bio-system based on the carbon nanotubes is possible and it paves the way for the appolication of carbon nanotubes.