Polyethylene Oxide – Polytetrafluorethylene Blends and their Nanofibers

Blends of (PEO) – Polytetrafluorethylene (PTFE) were obtained by adding PEO powder to the submicron water suspension of PTFE. Eventually, deionized water was added to facilitate the homogenization and to achieve an overall viscosity capable to sustain nanofiber production by force spinning. The PEO – PTFE mixture was homogenized by sonication. Films of PEO-PTFE were obtained by the removal of water in a vacuum oven at 50 °C, overnight. Mats of nanofibers of PEO-PTFE were obtained by force spinning of water solutions of PEO-PTFE blends at various concentrations. PEO has a glass transition of – 35 °C and a melting temperature of about 65 °C, while PTFE has a low glass transition of about – 100 °C and a very high melting temperature (about 335 °C). There is a controversy about the glass transition in PTFE with eventually an additional relaxation at about 116 °C. PTFE is among the few polymers that exhibit ferroelectric, piezoelectric, and pyroelectric capabilities. The stretching of the polymer solution (and implicitly of PTFE) during the force spinning is expected to result in the alignment of the PTFE chains within the mats. Because PTFE contains a larger number of F atoms per monomer than PVDF, it is expected that the local order in mats of PEO-PTFE will be stronger than in mats of PEO-PVDF, at the same spinning rate. Consequently, extended spectroscopic studies (by X – Ray diffraction, Raman and FTIR spectroscopy) were focused on the PEO-PVDF films and mats.

Electron microscopy images complemented by elemental analysis provided information about the morphology and composition of PEO-PTFE films and mats with emphasize on the distribution of F atoms.

Acknowledgments: We acknowledge the financial support for this research by National Science Foundation PREM Grant DMR 2122178.