Electrospinning of PVDF nanofibrous membranes with controllable crystalline phases

Effectively controlling crystalline phases of electrospun polyvinylidene fluoride (PVDF) nanofibers is crucial to produce membranes with special properties for specific applications. Here, the heating treatment during or after electrospinning has been investigated to determine an effective way to control crystalline phase of PVDF nanofibers. By simultaneously controlling the collector temperature and the flow rate during the fiber deposition, a comparatively lower temperature (≤70 °C) is required for obtaining α-, β-, or γ-phase-dominant nanofibrous membranes, whereas a much higher temperature (≥150 °C) is necessary for post-heating of already-deposited fibers. On the other hand, through finely tuning the heating during or after electrospinning, crosslinked nanofibrous membranes can be also obtained, which undoubtedly enhance mechanical performance of the membranes. Therefore, it is hopeful to fabricate high-performance electrospun PVDF nanofibrous membranes with synchronous control of crystalline phases and morphologies, which will further broaden the applications of PVDF materials.