Influence of preparation conditions on structural and dielectric properties of PVDF–MoS₂ nanotubes composite films

Poly(vinylidene fluoride) composite films with MoS₂ nanotubes were prepared from solutions using the doctor blade method and dried under various temperatures. While FTIR-ATR and Raman spectroscopy have revealed that composite films dried at room temperature are homogeneous and crystallize mainly in the γ-phase, a decrease in porosity upon addition of MoS₂ has been observed using scanning electron microscopy. Dielectric investigations revealed (i) a decrease from ε’ ∼ 7 in pure polymer to ε’ ∼ 4 in composite with 1 wt% of MoS₂, and (ii) a slight increase in ε’ and σ’ values upon further addition of MoS₂. Films dried at 110 °C were heterogeneous and FTIR-ATR has shown an increase in α-phase content upon addition of 1 wt% of MoS₂. In this case, high values of ε’ ∼ 10 that increased slightly upon increasing amount of MoS₂ in the film have been measured. By showing a direct relation between structure and dielectric response, it is suggested that the dielectric properties of poly(vinylidene fluoride)–MoS₂ nanotubes composites can be tailored by changing the preparation conditions.