A multifunctional polymer-based composite has been designed
based
on poly(vinylidene fluoride) (PVDF) as polymer matrix and cobalt ferrite
(CoFe2O4, CFO) and multiwalled carbon nanotubes
(MWCNTs) as fillers, allowing to combine magnetic and electrical responses.
The composites were prepared by solvent casting with a fixed 20 wt
% concentration of CFO and varying the MWCNTs content between 0 and
3 wt %, allowing to tailor the electrical behavior. The morphology,
polymer phase, and thermal and magnetic properties are nearly independent
of the MWCNT filler content within the polymer matrix. On the other
hand, the mechanical and electrical properties strongly depend on
the MWCNT content and a maximum d.c. electrical conductivity value
of 4 × 10–4S·cm–1has
been obtained for the 20 wt %CFO-3 wt %MWCNT/PVDF sample, which is
accompanied by an 11.1 emu·g–1magnetization.
The suitability of this composite for magnetic actuators with self-sensing
strain characteristics is demonstrated with excellent response and
reproducibility.