Thermoelectric properties of polypropylene carbon nanofiber melt-mixed composites: exploring the role of polymer on their Seebeck coefficient

authors	Paleo, AJ; Krause, B; Cerqueira, MF; Melle-Franco, M; Potschke, P; Rocha, AM
nationality	International
journal	POLYMER JOURNAL
keywords	N-TYPE; P-TYPE; CONDUCTIVITY; NANOTUBES; PERFORMANCE; FABRICATION; POWER
abstract	The effect of polypropylene (PP) on the Seebeck coefficient (S) of carbon nanofibers (CNFs) in melt-extruded PP composites filled with up to 5 wt. % of CNFs was analyzed in this study. The as-received CNFs present an electrical conductivity of similar to 320 S m(-1) and an interesting phenomenon of showing negative S-values of -5.5 mu VK-1, with 10(-2) mu W/mK(2) as the power factor (PF). In contrast, the PP/CNF composites with 5 wt. % of CNFs showed lower conductivities of similar to 50 S m(-1), less negative S-values of -3.8 mu VK-1, and a PF of 7 x 10(-4) mu W/mK(2). In particular, the change in the Seebeck coefficient of the PP/CNF composites is explained by a slight electron donation from the outer layers of the CNFs to the PP molecules, which could reduce the S-values of the as-received CNFs. Our study indicates that even insulating polymers such as PP may have a quantifiable effect on the intrinsic Seebeck coefficient of carbon-based nanostructures, and this fact should also be taken into consideration to tailor conductive polymer composites with the desired thermoelectric (TE) properties.
publisher	SPRINGERNATURE
issn	0032-3896
isbn	1349-0540
year published	2021
volume	53
issue	10
beginning page	1145
ending page	1152
digital object identifier (doi)	10.1038/s41428-021-00518-7
web of science category	8
subject category	Polymer Science
unique article identifier	WOS:000663986000001