X-ray photoelectron spectroscopy (XPS) has been used to investigate the sur
face chemical state of two carbon nanotube materials and determine the evid
ence of surface modification from a reaction with dichlorocarbene. Carbon a
nd oxygen were the major elements observed on the surface of the pristine c
arbon nanotube produced by electric arc discharge. After reaction with dich
lorocarbene, chlorine atoms amounting to about 1.6 at.% were detected and t
he peak position of Cl 2p was at 201.3 eV, which can be attributed to exist
ence of organic chlorocarbons. A new intense peak addition to the peak at 2
85 eV for the elemental sp(2) and sp(3) carbon atoms appears at the binding
energy of about 287.5 eV in the C 1s narrow scan spectrum. This binding en
ergy is typical for C 1s ionization of sp(3) carbon in organic chlorocarbon
s. It was found that C-C was the major carbon functional component in the s
urface modified carbon nanotube but other functional forms of carbon were a
lso present such as C-Cl, C-O, and O-C=O. With Ar+ ion sputtering, the atom
ic percent concentration of chlorine decreased by 65%, the carbon concentra
tion increased significantly and the oxygen surface concentration decreased
from 20.7 to 5.5 at.%. The surface chemical treatment with dichlorocarbene
has thus modified the surface of the carbon nanotube with localization of
small amounts of chlorine atoms on the carbon surface without disrupting th
e single walled nanotube bundles. (C) 2001 Elsevier Science B.V. All rights
reserved.