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.