Modification of nanotubes oxidation with peroxygen compounds
View Patent ↗A method of chemically modifying carbon nanotubes having a diameter less than one micron comprising: contacting the nanotubes with a peroxygen compound selected from the group consisting of organic peroxyacids, inorganic peroxoacids and organic hydroperoxides, or a salt thereof, under oxidation conditions and thereby producing modified carbon nanotubes. Oxidation of the nanotubes increases the degree of dispersion of aggregates of nanotubes and aids in the disassembling of such aggregates. The dispersed nanotubes are used to prepare rigid structures and can be used in electrodes and capacitors.
1. A method of chemically modifying carbon nanotubes having a diameter less than one micron comprising: contacting the nanotubes with a peroxygen compound selected from the group consisting of organic peroxyacids, inorganic peroxoacids and organic hydroperoxides, or a salt thereof, under oxidation conditions and thereby producing modified carbon nanotubes, and functionalizing said modified carbon nanotubes with a reactant suitable for adding at least one additional type of functional group to the surface of said nanotubes.
2. A method as recited in claim 1 , wherein the diameter of said nanotubes is from 3.5 to 75 nanometers.
3. A method as recited in claim 2 , wherein said nanotubes are substantially cylindrical and include a plurality of graphitic layers that are substantially parallel to the axis of said nanotubes and have a length to diameter ratio of greater than 5.
4. A method as recited in claim 2 , wherein said carbon nanotubes are substantially free of a continuous pyrolitically deposited carbon overcoat.
5. A method as recited in claim 1 wherein the said additional functional groups are alkyl/aralkyl, hydroxyl, amine, alkyl aryl silanes and fluorocarbon groups having from 1 to 18 carbons.
6. A method as recited in claim 1 , wherein the peroxygen compound is selected from the group consisting of: (a) an inorganic peroxoacid; (b) a peroxycarboxylic acid of the formula Q(C(O)OOH) n ; (c) a hydroperoxide of the formula Q(OOH) n ; (d) salts of (a), (b) or (c), and (e) combinations of any of (a), (b), (c) or (d), wherein Q is an alkyl, aralkyl, cycloalkyl, aryl or heterocyclic group having from 1 to 12 carbon atoms, and n is 1 or 2.
7. A method as recited in claim 6 , wherein the inorganic peroxoacid or salt thereof is selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, ammonium dichromate, potassium dichromate, sodium dichromate, peroxysulfuric acid, potassium peroxymonosulfate, ammoniuni peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate.
8. A method as recited in claim 6 , wherein the peroxycarboxylic acid is selected from the group consisting of peracetic acid, m-chloroperoxy benzoic acid, magnesium monoperoxyphthalate hexahydrate, performic acid, perbenzoic acid and salts thereof.
9. A method as recited in claim 6 , wherein the peroxycarboxylic acid is peracetic acid.