High crystallinity and polar-phase content in electrospun P(VDF-TrFE) nanofibers with low molecular weight.

Electrospun piezoelectric nanofibers from polyvinylidene fluoride (PVDF) have been widely used in many applications. In PVDF-based polymers, the molecular weight (M_w) plays an important role in determining both crystallization and polarization responses. In the past, polyvinylidene fluoride trifluoroethylene [P(VDF-TrFE)] electrospun nanofibers were produced strictly from high molecular weight polymers (M_w > 200 kDa). Here, we study the electrospun P(VDF-TrFE) nanofibers from comparatively lower M_w polymers (M_w ∼ 100 kDa). We demonstrated a highly electroactive phase in electrospun P(VDF-TrFE) nanofibers without post treatments. During electrospinning, shorter P(VDF-TrFE) polymer chains exhibited higher mobility, which facilitate the formation of all-trans ferroelectric crystals with high crystallinity. By optimizing the mean size of electrospun nanofiber through tailoring the solution concentration and other controlling parameters, P(VDF-TrFE) nanofibers achieved the crystallinity as high as 67% and all-trans conformation reached 79%. The results pave a way for improving the electroactive performance in ferroelectric polymer electrospun nanofibers.