Study On Temper CVD Preparation Of Aligned Carbon Nanotubes And Its Drag Reduction To Micro-Fluid

Carbon nanotubes (CNTs) has received much attention of experts in many fields due to its high mechanical strength, good electrical and thermo conductivity, excellent preservation for hydrogen gas. Because it has nanometer dimension, research about it has come to chemical-modification for that it can be used in micro-fluidics.In this paper, aligned carbon nanotubes was grown on smooth silicon substrate by decompositing acetylene using chemical vapor deposition both with nickel, cobalt as catalyst and ferrocene as catalyst precursor. The parameter was also investigated in the preparation, such as ammonia, buffering-gas, temperature and the quantity of catalyst. The result is that aligned carbon nanotubes can be grown with both methods. In the preparation, ammonia not only reacted with catalyst but also removed amporphous carbon in the formation stage of carbon nanotubes. The higher the temperature was, the more the carbon resource decomposed fully, the less amorphous carbon was formed. The sufficient catalyst is necessary so that the carbon nanotubes was highly compact to grow in one direction. If the quantity of catalyst was reduced, the carbon nanotube would bend and aligned carbon nanotubes could not be perarated.The impregnation and the resistance to fluid of carbon nanotubes were also studied with contact angle system and rheometer. Both aligned and non-aligned carbon nanotubes are surperhydrophobic. The compacter the carbon nanotubes was, the higher the contact angle was. After treated with silane, the contact angle was slightly improved. The carbon nanotubes is oleophobic and the contact angle with glycerine was 110°. The carbon nanotubes can reduce drag significantly not only in water flow but also in glycerine flow compared with smooth silicon substrate. Carbon nanotubes surface demonstrated a dramatic slip effect, tens of micrometers in water flow and about 100μm in glycerin.