Nonlinear Thermopower Behaviour of N-Type Carbon Nanofibres and Their Melt Mixed Polypropylene Composites
| Autor: | Antonio J. Paleo, Beate Krause, Maria F. Cerqueira, Enrique Muñoz, Petra Pötschke, Ana M. Rocha |
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| Přispěvatelé: | Universidade do Minho |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
Variable range hopping
Science & Technology Polymers and Plastics polypropylene carbon nanofibers thermoelectric properties n-type polymer composites variable range hopping Organic chemistry 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Article 0104 chemical sciences QD241-441 Carbon nanofibers Thermoelectric properties N-type polymer composites Polypropylene 0210 nano-technology |
| Zdroj: | Polymers, Vol 14, Iss 269, p 269 (2022) Polymers; Volume 14; Issue 2; Pages: 269 Polymers Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| ISSN: | 2073-4360 |
| Popis: | The temperature dependent electrical conductivity σ (T) and thermopower (Seebeck coefficient) S (T) from 303.15 K (30 °C) to 373.15 K (100 °C) of an as-received commercial n-type vapour grown carbon nanofibre (CNF) powder and its melt-mixed polypropylene (PP) composite with 5 wt.% of CNFs have been analysed. At 30 °C, the σ and S of the CNF powder are ~136 S m−1 and −5.1 μV K−1, respectively, whereas its PP/CNF composite showed lower conductivities and less negative S-values of ~15 S m−1 and −3.4 μV K−1, respectively. The σ (T) of both samples presents a dσ/dT < 0 character described by the 3D variable range hopping (VRH) model. In contrast, their S (T) shows a dS/dT > 0 character, also observed in some doped multiwall carbon nanotube (MWCNT) mats with nonlinear thermopower behaviour, and explained here from the contribution of impurities in the CNF structure such as oxygen and sulphur, which cause sharply varying and localized states at approximately 0.09 eV above their Fermi energy level (EF). Antonio J. Paleo gratefully acknowledges support from FCT-Foundation for Science and Technology by the “plurianual” 2020–2023 Project UIDB/00264/2020. E. Muñoz acknowledges support from Fondecyt grant number 1190361 and from ANID PIA Anillo ACT/192023. |
| Databáze: | OpenAIRE |
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