Enhancing the superhydrophobic behavior of electrospun fibers via graphene addition and heat treatment

Abstract

Polyvinyl chloride (PVC) fibers incorporated with graphene nanoflakes were produced using electrospinning technique, and then superhydrohobicity of the electrospun nanofibers were investigated as a function of inclusion and temperature. In the absence of graphene, water contact angle of the fibers is below 1400; however, the water contact angle values of 0.5, 1, 2 and 4% graphene in fibers become 142, 152, 165 and 166, respectively. Using a heat treatment, the contact angle values of samples also increase up to glass transition temperature of PVC. This indicates that graphene inclusions in the polymeric fibers and temperature drastically change the surface morphology and chemistry, which results in higher contact angles. The reason behind this phenomena may be the formation of smaller nanosized graphene bumps on the fiber surface that make the contact area between the droplet and the fiber extremely small. As a result, this process minimizes attractive forces between the water molecules and surface atoms of the rough nanocomposite fibers to bead up and rolls off.