Investigations into polymeric materials as flexible thermoelectric (TE)
materials have encountered issues, such as conflicting thermoelectric property
behaviors that result in a low power factor. To tackle these issues, we propose
the use of two unique sorts of fillers - carbon nanotubes (CNT) and silica
particles -- embedded in polymer matrix for enhanced TE properties. Embedding
micro-scale segregated structures as the secondary fillers creates an excluded
volume within CNT networks, which leads to the simultaneous increase in the
electrical conductivity and Seebeck coefficient of the composite.
Polydimethylsiloxane (PDMS) is used as a suitable matrix because of its merits
such as solution processability, light weight, low thermal conductivity and an
internet of things. As silica content increased up to 40 wt%, electrical
conductivity and Seebeck coefficient increases in the segregated composite
framework, resulting in maximum power factor of approximately 25.96 and 42.89
microW/mK2 for 1 and 3 micrometer size silica particles, respectively.
Moreover, using much lower CNT content, such as 10 wt% CNT stacking, results at
a desired level of electrical conductivity and Seebeck coefficient. This study
ultimately develops the hypothesis that the network topology of CNT-based
polymer composites depends on the size and characteristics of the secondary
fillers