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Electromechanical characterization of magnetic responsive and conductive 353

loadings were used for the fabrication of films, solutions A and B. Solution A contains
0.5 wt.% of PEDOT and 0.8 wt.% of PSS in the dispersion, whereas Solution B contains
a lower percentage of PSS. The films from solution A, cracked significantly even on
glass slides, while the films obtained from solution B resulted in a uniform film
(Fig. 15.3). Such an occurrence is due to the different concentrations of PEDOT and PSS
in the solutions. While both solutions contain 1.3 wt.% dispersion of PEDOT:PSS in
water, the PEDOT and PSS weights in solution A are known to be 0.5 and 0.8 wt.%,
respectively. Meanwhile, the individual weights of PEDOT and PSS in the solution from
solution B are unspecified. However, since the concentration of PSS in solution B is
higher, it aids in the physical crosslinks between PEDOT molecules and PSS chains to
improve the stability of the films. Unfortunately, a higher concentration of PSS also
implies a lower concentration of PEDOT. As PEDOT is responsible for the conductivity
of the films, there is a trade-off between the stability and the conductivity of the
fabricated films.

Figure 15.2
PEDOT:PSS/Fe 3 O 4 1:5 films cast on the 3D printed mold (left) and a glass substrate (right).

Figure 15.3
PEDOT:PSS/Fe 3 O 4 1:1 films cast with solution A (left) and solution B (right).