Influence of chlorotrifluoroethylene on crystal structure and polymer dynamics of poly(vinylidenefluoride-co-chlorotrifluoroethylene) antibacterial copolymers

The effect of chlorotrifluoroethylene (CTFE) on dynamic relaxations of poly(vinylidenefluoride-co-chlorotrifluoroethylene) films (P(VDF-CTFE)) containing 0, 10, 15 and 20% of CTFE was investigated via broadband dielectric spectroscopy (DRS) and dynamic mechanical analysis (DMA). The interpretation was accompanied by the crystal structure obtained from Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, small-angle X-ray scattering and differential scanning calorimetry. Increment of CTFE contents caused reducing the degree of crystallinity but did not impact the long period, lamellar thickness, and amorphous layer thickness. Four dynamic processes were clearly observed in DRS spectra for the neat poly(vinylidene fluoride) and P(VDF-CTFE) which were attributed to the local motion of amorphous chains (β), the segmental relaxation of amorphous chains (α₁), the local conformational rearrangement of the TGTGʹ conformation (α₂) and the process associated with Maxwell–Wagner–Sillars interfacial polarization (α_MWS). The extra relaxation was observed for P(VDF-CTFE), which was more likely associated to the molecular motion of CTFE chain segments (α_c), correspondent with DMA results. These PVDF and P(VDF-CTFE) conducted as self-antibacterial materials.