CNT Filament Formation By Buoyancy Induced Extensional Flow

1 . A method for producing elongated non-entangled nanotube filaments comprising:

(i) introducing a fluid mixture into a lower portion of a vertically orientated reactor at least partially filled with a pre-heated dense gas, wherein the fluid mixture comprises (a) a metal catalyst precursor, (b) a conditioner compound, and (c) a carbon source;

(ii) propelling the fluid mixture upwardly through the vertically oriented reactor;

(iii) initiating decomposition of the metal catalyst precursor into metal catalyst particles and the carbon source into carbon atoms;

(iv) allowing the carbon atoms to be deposited onto the metal catalyst particles to form elongated non-entangled nanotube filaments; and

(v) discharging the elongated non-entangled nanotube filaments from an upper portion of the vertically orientated reactor.

2 . The method of claim 1 , wherein the dense gas comprises argon, sulfur hexafluoride (SF 6 ), carbon monoxide, or a combination thereof.

3 . The method of claim 1 , wherein the concentration of the dense gas in the vertically oriented reactor is at least 10 mole percent.

4 . The method of claim 1 , wherein the bottom half of the vertically oriented reactor is substantially filled with the dense gas.

5 . The method of claim 1 , wherein the metal catalyst precursor is ferrocene.

6 . The method of claim 1 , wherein the conditioner compound comprises thiophene, H 2 S, other sulfur containing compounds, or a combination thereof

7 . The method of claim 1 , wherein the fluid mixture is introduced at volumetric flow rate of 1 to 5 standard liter per minute.

8 . A vertically orientated upward flow floating catalyst chemical vapor deposition system for producing elongated nanotube filaments comprising (i) a vertically oriented reactor having a lower end, an upper end and an inner cavity containing a dense gas; (ii) an injector positioned at the lower end of the vertically oriented reactor configured for propelling a fluid mixture upwardly into the vertically oriented reactor, the fluid mixture comprising a) a metal catalyst precursor, (b) a conditioner compound, and (c) a carbon source, (iii) a furnace surrounding the vertically oriented reactor, and (iv) a collection unit positioned at the upper end of the vertically oriented reactor configured to collect the elongated nanotube filaments produced within the vertically oriented reactor.

9 . The system of claim 8 , wherein the dense gas comprises argon, sulfur hexafluoride (SF 6 ), carbon monoxide, or a combination thereof.

10 . The system of claim 8 , wherein the concentration of the dense gas in the vertically oriented reactor is at least 10 mole percent.

11 . The system of claim 8 , wherein the bottom half of the vertically oriented reactor is substantially filled with the dense gas.