This review describes state-of-the-art scientific and technological developments of electrospun nanofibers and their use in self-cleaning membranes, responsive smart materials, and other related applications.Superhydrophobic self-cleaning, also called the lotus effect, utilizes the right combinations of surface chemistry and topology to form a very high contact angle on a surface and drive water droplets away from it. The high-contact-angle water droplets easily roll off the surface, carrying with them dirt, particles, and other contaminants by way of gravity. A brief introduction to the theory of superhydrophobic self-cleaning and the basic principles of the electrospinning process is presented. Also discussed is electrospinning for the purpose of creating superhydrophobic self-cleaning surfaces under a wide variety of parameters that allow effective control of roughness of the porous structure with hydrophobic entities. The main principle of electrospinning at the nanoscale and existing difficulties in synthesis of one-dimensional materials by electrospinning are also covered thoroughly. The results of different electrospun nanofibers are compared to each other in terms of their superhydrophobic properties and their scientific and technological applications.

Mechanically durable, long-lasting antifog coatings based on polysaccharides were developed using a layer-by-layer (LBL) assembly process. The unique properties of these coatings are a result of a molecular-level blending of the polysaccharides, with multilayers containing chitosan and carboxymethyl cellulose providing the best overall properties. The antifog properties resulted from a strong interaction between the polar and H-bonding elements of the assembled polymers and water molecules and the concomitant formation of thin films of water. Environmental scanning electron microscopy (ESEM) studies confirmed that fogging coatings are decorated with light scattering, micrometer-sized droplets of water whereas antifogging coatings remain droplet free. To improve the mechanical durability of the multilayer films on substrates, the surface was modified via self-assembly of epoxy-functionalized silane molecules. Cross-linking chemistry was then applied to improve the mechanical robustness of the LBL films on various surfaces. These films were characterized using several techniques: optical profilometery (PL), spectroscopic ellipsometry (EL), contact angle goniometry (CA), and atomic force microscopy (AFM). The antifog properties of the films were evaluated by several tests under different environmental conditions. This work demonstrates that the unique water-adsorbing properties of polysaccharides can be exploited to create permanent antifog properties, which may be useful for various applications.

Polystyrene (PS) and polyvinyl chloride (PVC) fibers incorporated into TiO(2) nanoparticles and graphene nanoflakes were fabricated by an electrospinning technique, and then the surface morphology and superhydrophobicity of these electrospun nanocomposite fibers were investigated. Results indicated that the water contact angle of the nanocomposite fiber surfaces increases to 178° on the basis of the fiber diameter, material type, nanoscale inclusion, heat treatment, and surface porosity/roughness. This is a result of the formation of the Cassie-Baxter state in the fibers via the nanoparticle decoration, bead formation, and surface energy of the nanofiber surface. Consequently, these superhydrophobic nanocomposite fibers can be utilized in designing photoelectrodes of dye-sensitized solar cells (DSSCs) as self-cleaning and anti-icing materials for the long-term efficiency of the cells.

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This paper presents an idea of using carbonized electrospun Polyacrylonitrile (PAN) fibers as a sensor material in a structural health monitoring (SHM) system. The electrospun PAN fibers are lightweight, less costly and do not interfere with the functioning of infrastructure. This study deals with the fabrication of PAN-based nanofibers via electrospinning followed by stabilization and carbonization in order to remove all non-carbonaceous material and ensure pure carbon fibers as the resulting material. Electrochemical impedance spectroscopy was used to determine the ionic conductivity of PAN fibers. The X-ray diffraction study showed that the repeated peaks near 42° on the activated nanofiber film were α and β phases, respectively, with crystalline forms. Contact angle, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were also employed to examine the surface, thermal and chemical properties of the carbonized electrospun PAN fibers. The test results indicated that the carbonized PAN nanofibers have superior physical properties, which may be useful for structural health monitoring (SHM) applications in different industries.