Abstract The cross-plane thermoelectric properties of multi-walled carbon nanotubes-poly(vinylidene fluoride) (MWCNT-PVDF) nanocomposites were investigated at room temperature as a function of MWCNT content (from 5 to 50 wt%). Special attention was paid to the influence of the nature of the polymer crystal phase. Incorporation of MWCNT induces PVDF polar β-phase formation, coexisting with the major non polar α-phase. Significant improvement of the thermoelectric properties is evidenced, with the best values obtained at 50 wt% MWCNT loading. A post treatment at high temperature (T =165 °C) results in the development of the polar γ-phase from the α- and β-polymorphs. Nanocomposites annealing significantly enhances the Seebeck coefficient, typically from 14 up to 20 μV K−1, yielding a power factor of 4.6 × 10−2 μW m−1 K−2 and a figure of merit ZT of 1.6 × 10−5 at 50 wt%, which is the best ZT value that can be found in the literature, regarding MWCNT-PVDF bulk nanocomposites. Structural analysis underlines for the first time the impact of the polymer polar γ-phase on the nanocomposite thermoelectric properties.

中文翻译：

---

块状多壁碳纳米管-聚偏二氟乙烯纳米复合材料的热电性能：结构/性能关系研究

摘要 研究了多壁碳纳米管-聚偏二氟乙烯 (MWCNT-PVDF) 纳米复合材料在室温下作为 MWCNT 含量（5 至 50 wt%）的函数的横断面热电性能。特别注意聚合物晶相性质的影响。MWCNT 的掺入诱导 PVDF 极性 β 相的形成，与主要的非极性 α 相共存。证明了热电性能的显着改善，在 50 wt% MWCNT 负载下获得了最佳值。在高温 (T = 165 °C) 下进行后处理会导致极性 γ 相从 α- 和 β- 多晶型物发展而来。纳米复合材料退火显着提高了塞贝克系数，通常从 14 到 20 μV K-1，产生 4 的功率因数。6 × 10−2 μW m−1 K−2 和 50 wt% 时的品质因数 ZT 为 1.6 × 10−5，这是文献中可以找到的关于 MWCNT-PVDF 块状纳米复合材料的最佳 ZT 值。结构分析首次强调了聚合物极性 γ 相对纳米复合材料热电性能的影响。