Decoupling the trade-off between thermoelectric and mechanical performances for polymer composites via interfacial regulation

Abstract

Despite the explosive achievements in thermoelectric (TE) composites, their mechanical (ME) performance has received little attention relative to the significant enhancement of the TE performances. Furthermore, there always exists a trade-off between TE and ME performances, i.e., both are difficult to be improved simultaneously. Herein, we realize the decoupling of the trade-off between TE and ME performances for flexible polycarbonate (PC)/single-walled carbon nanotube (SWCNT) composites via interfacial adjustment. The barrel-shaped droplet-like PC granules are observed on the surfaces of the acid-treated SWCNTs (a-SWCNTs), indicating high wettability and interfacial affinity. The obtained PC/a-SWCNT composite displays a maximum power factor (PF) value of 6.2 μW m−1 K−2, which distinctly overmatches the PC/pristine SWCNT (p-SWCNT) with a PF value of 4.8 μW m−1 K−2. In addition, the composites reveal the increments of 22% and 16% in the fracture strength and tensile modulus over the PC/p-SWCNT composite, respectively. This decoupling of the trade-off is ascribed to the high electrical conductivity of a-SWCNTs and the strong interfacial interaction between PC and a-SWCNTs. The present work provides an easy and promising methodology to decouple the intractable trade-off issue of TE and ME performances and benefits their practical TE applications.