II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-13
SYNTHESIS AND ELECTROCHEMICAL STUDY OF SINGLE-WALLED
NANOTUBE-POLYACETYLENE COMPOSITE
Efimov O.N., Tkachenko L.I.
Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia
e-mail: efimov@icp.ac.ru
The work is aimed at the preparation of composite materials comprising single-walled
nanotubes (SWNT) (2.4 w/w. %) covered with polyacetylene (PA) using the method of
polymerization filling [1], and the study of electrochemical intercalation-deintercalation of
lithium in these composites. We showed [2] that the insertion of electroconducting filler,
namely, graphite, SWNT and multi-walled nanotubes (MWNT) into starting PA by
mechanical blending sharply enhances conductivity. A percolation threshold for PA-SWNT
composites [2] is close to 3 v/v.% and is somewhat lower that for composites filled with
graphite. This effect was called “physical” doping in [2, 3]. The increase of conductivity from
10 -1 to 10 0 Sּcm -1 was interpreted by the authors to be due to the injection of electrons to PA
from filler particles. According to [4], the calculation shows that there is a portion of
increased charge density between a PA chain and a wall of SWNT.
In the present work we synthesized PA directly on SWNT in the presence of a Ziegler
catalyst, Al(i-C 4 H 9 ) 3 and Ti(OBu) 4 , in toluene ([Al]/[Ti]= 4/1, [Ti] = 3⋅10 -3 mole/l). SWNT
were prepared by an arc discharge method and purified from by-products (catalyst, soot
particles, and amorphous carbon) to yield a material with mass content of nanotubes equal to
80-90%.
Composite morphology was characterized using a JEM- 100 CX transmission electron
microscope. The composite was found to consist of SWNT covered by a polyacetylene shell.
An average diameter of structural units of the
composite was determined to be ≈ 80 nm. No free
polyacetylene was observed between the tubes
covered by PA. This indicates that polymerization
occurs only on SWNT possibly due to the
adsorption of catalytic centers on an outer surface of
SWNT. Such adsorption can be accompanied by
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