Three-dimensional structured superhydrophobic electrospun nanofiber mats for environmental remediations

Abstract

This research is focused on the production of nanofibers from the electrospinning process with and without a Teflon™ emulsion. Research on superhydrophobic surfaces and its applications in different fields has garnered keen interest around the globe. Among the various processes of fabricating a superhydrophobic surface, electrospinning is the most simple and versatile method for producing these fibers. In this study, polystyrene (PS) and polyvinyl chloride (PVC) were separately dissolved in dimethylformamide (DMF) and dimethylacetamide (DMAc), respectively, to prepare polymeric solutions for electrospinning. Different volumes (2 ml, 4 ml, and 8 ml) of a Teflon™ emulsion were allowed to dry so that all aqueous content evaporated, leaving behind only solid particles 0.18 μm in size, which were added to the polymer solution prior to the electrospinning. Here, Teflon™ was used to increase the hydrophobicity of the fibers. The polymer solution with and without Teflon™ particles were electrospun to obtain three-dimensional (3D)-structured fibers. The diameter of the PS fibers ranged from 400 nm to 1 μm, and the PVC fiber ranged from 200 to 600 nm. These nanofibers were then heat treated at different temperatures (50°C, 75°C, 100°C, and 125°C) and different time intervals (30 minutes, 1 hour, 2 hours, and 4 hours). The hydrophobicity of the fibers was investigated by contact angle measurement. Results indicate that all the fibers were hydrophobic in nature. With the addition of Teflon™ particles along with heat treatment, the water contact angle for the PS fibers increased to 155.75° and for the PVC fibers increased to 151.62°, confirming that the fibers were superhydrophobic in nature. The nanofibers were further characterized by using scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy to study their surface morphology and chemical composition. All fibers were in the submicron and nanoscale ranges with Teflon™ particles uniformly distributed and can be used for different applications.