Effect of the Linking Group on the Thermoelectric Properties of Poly(Schiff Base)s and Their Metallopolymers

As polymer-based thermoelectric (TE) materials possess attractive features such as light weight, flexibility, low toxicity and ease of processibility, an increasing number of conducting polymers and their composites with high TE performances have been developed in recent years. Up to date, however, the research focusing on the structure-performance relationship remains rare. In this paper, two series of poly(Schiff base)s with either C=C or C≡C linker and their metallopolymers were synthesized and doped with single-walled carbon nanotubes to evaluate how the linking groups affected the TE properties of the resulting composites. Apart from the effect exerted by the morphology, experimental results suggested that the linkers played a key role in determining the band gaps, preferred molecular conformation and extent of conjugation of the polymers, which became key factors that influenced the TE properties of the resulting materials. Additionally, upon coordination with transition metal ions, the TE properties could be tuned readily.