Coaxially Electrospun PVDF−Teflon AF and Teflon AF−PVDF Core−Sheath Nanofiber Mats with Superhydrophobic Properties

Abstract

This work reports the coaxial electrospinning of poly(vinylidene fluoride) (PVDF)-Teflon amorphous fluoropolymer (AF) and Teflon AF-PVDF core-sheath nanofiber mats yielding superhydrophobic properties. The coaxial electrospinning configuration allows for the electrospinning of Teflon AF, a nonelectrospinnable polymer, with the help of an electrospinnable PVDF polymer. PVDF-Teflon AF and Teflon AF-PVDF core-sheath fibers have been found to a have mean fiber diameter ranging from 400 nm to less than 100 nm. TEM micrographs exhibit a typical core-sheath fiber structure for these fibers, where the sheath fiber coats the core fiber almost thoroughly. Water contact angle measurements by sessile drop method on these core-sheath nanofiber mats exhibited superhydrophobic characteristics with contact angles close to or higher than 150 degrees. Surprisingly, PVDF-Teflon AF and Teflon AF-PVDF nanofiber mat surface properties were dominated by the fiber dimensions and less influenced by the type of sheath polymer. This suggests that highly fluorinated polymer Teflon AF does not advance the hydrophobicity beyond what surface physics and slightly fluorinated polymer PVDF can achieve. It is concluded that PVDF-Teflon AF and Teflon AF-PVDF core-sheath electrospun nanofiber mats may be used in lithium (Li)-air batteries.

Literature review on superhydrophobic self‐cleaning surfaces produced by electrospinning

“…Muthiah et al 92 also studied coaxial electrospinning for superhydrophobic application. In addition to Teflon AF, they used another fluorinated compound (PVDF) as a second polymer and considered both configurations: Teflon AF as a sheath and as a core polymer.…”

Preparation and Characterization of Polyvinylidene Fluoride/Graphene Superhydrophobic Fibrous Films

“…In addition to the above, electrospinning is also a predominant and promising technique to develop superhydrophobic surfaces from some polymers with low surface energies and introducing the hierarchical structure to them. In recent years, several types of superhydrophobic surfaces, produced by electrospinning of PVDF, have been reported in the literature [21][22][23][24][25][26]. Additionally, it will be a good task to obtain a kind of novel film with PVDF/graphene electrospun thin layers coated on the surface of porous supports like polypropylene (PP) and polytetrafluoroethylene (PTFE).…”

Preparation of a durable superhydrophobic membrane by electrospinning poly (vinylidene fluoride) (PVDF) mixed with epoxy–siloxane modified SiO2 nanoparticles: A possible route to superhydrophobic surfaces with low water sliding angle and high water contact angle

“…Hence, PVDF membrane is widely used in structural material coating applications, such as the surface materials of vehicle, boots, raincoat, and the cover of outdoor airconditioner [29,30]. In the future, with the coating layer with self-cleaning property, the PVDF membranes will be able to be fabricated, the dusts on which will be easily washed away by rain, thus saving a great deal of manpower and cost for cleaning services [31][32][33][34][35][36][37].…”