Hybrid polypyrrole (PPy)–multi walled carbon
nanotube (MWNT) yarns were obtained by chemical
and electrochemical polymerization of pyrrole on the
yarn surface. The material was characterized by
SEM imaging, electrochemical, mechanical and
electrical measurements. It was found that the hybrid
PPy-MWNT yarns possess significantly higher
mechanical strength (over 740 MPa) and Young’s
modulus (over 54 GPa) and than the pristine MWNT
yarn. The material also exhibited substantially
higher electrical conductivity (over 23500 S/m).
Specific capacitance for PPy-MWNT yarn was
found over 60 F/g. Measurements of temperature
dependences of electrical conductivity revealed
metallic behaviour at high temperature and
semiconducting behaviour at low temperature with
the metal-to- insulator transition near 100 K. The
collected low temperature data are in the good
agreement with variable range hopping model (3DVRH).
The improved durability of the yarns is
important for electrical applications. The composite
yarns can be produced in commercial quantities and
used for the applications where the electrical
conductivity is of primary importance.