1. 1 Covalent chemistry of single walled nanotubes Krishna Prasad Bastola, Graduate Student, Chemistry Department Oklahoma State University

2. 2 SWNTs:  High metallic conductivity.  High tensile strength, high elasticity.  High chemical and thermal stability.  Ability to absorb gas molecules as nano capillaries.

3. 3 Other applications of SWNTs need chemical modification Two types of chemical modification :  non covalent interaction  Covalent Interaction (functionalization of SWNTs)

4. 4 Solubility of SWNT as such in different solvents is about 5mg/50 ml. Solubility increases to 1mg/ml after functionalization. Attachment of desired moieties in SWNTs possible only in solution. AFM of functionalized tube AFM of unfunctionalized tube Source:Texas institutes for intelligent bio nanomaterials, NASA

5. 5 Steps involved in functionalization Introduction of COOH groups Changing COOH to COCl Amidation of COCl by amine such as octadecylamine(ODA) Source: J. Mater. Chem.2002,1952

6. 6 Schematics of functionalization route.

7. 7 Characterization of functionalized SWNTs  No standard techniques yet.  ATR good tools to identify functional groups (FG)  NMR has some application but to interpret spectra is difficult  Raman spectroscopy is useful specially for the (FG) in side wall of SWNT  TGA ( thermal gravimetric analysis) used extensively as the FG are labile.  SEM,AFM, TEM, and STM microscopy's are also very useful.

8. 8 Potential applications of functional SWNTs. Fluorinated SWNTs as cathode in lithium electrochemical cell. Polyethyleneimine-SWNT in neuronal growth Functionalized SWNT as CFM tips

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10. 10 Thank You very much