Surface-modified polyacrylonitrile nanofibres as supports

Abstract

Polyacrylonitrile nanofibers ( PAN-nfs) are one of t he most studied nanofibres because of their excellent characteristics, such as good mechanical strength, chemical resistance, and good thermal stability. Due to the easy dissolution in polar organic solvents, PAN-nfs are mostly produced via electrospinning technique. The electrospun PAN-nfs surfaces are relatively in-active and hydrophobic, and, therefore, hinder some potential applications; however, chemical surface modification reactions, such as amination, reduction, hydrolysis, and amidoximation, have been carried out on them. These reactions bring about functional groups, such as amine, hydroxyl, carboxylic, imine etc, to the surface PAN-nfs and invariably make their surfaces active and hydrophilic. The surface-modified PAN-nfs have been used as supports for organic compounds, enzymes, and antibodies in biological studies. They have also been used for immobilization of various organic ligands for adsorption of metal ions in water. Furthermore, because of their ability to complex metal ions, several surface-modified PAN-nfs have also been used as supports for transition metal catalysts in Fenton's chemistry.

Photocatalytic and antifouling properties of electrospun TiO2 polyacrylonitrile composite nanofibers under visible light

“…At these diameters, nanofibers exhibit characteristics such as high surface area to volume rate. Electrospinning can produce polymer nanofibers in a continuous mode [27][28][29][30]. Other methods such as self-assembly, chemical vapor deposition, template-assisted synthesis and wet chemical synthesis have also been used to produce nanofiber materials, however, electrospinning possess advantages such as allowing easy doping, simplicity, low cost, and high reproducibility [31].…”

Controlling Release Kinetics of Payloads from Polymer Conjugates by Hydrophobicity

“…Hydrogels prepared via imine‐crosslinking of hydrophilic polymers showed self‐healing properties because of fast formation/cleavage of imine linkages . Additionally, imine bonds are suitable linkages for modifying the surface of substrates by grafting . Moreover, numerous reports are related to the conjugation of payloads to hydrophilic and amphiphilic backbones or inorganic nanoparticles by imine and hydrazone linkages .…”

Immobilization of Metal Selective Ligands upon Polymer Nanofibers: Successes and Challenges

“…The surface modification of nanofiber-based adsorbents has been reported in the literature [3,4]. In surface modification, surface chemical compositions and characteristics are altered either for general purposes or for specific purposes [5]. There are two main approaches for the surface modification of nanofiber materials.…”

“…Many modification processes may be too harsh to maintain delicate nanofiber integrity. The nanofibers should be handled properly to ensure that the porous and large surface areas are not compromised during modifications and applications [5].…”

“…The nanofiber support should be physically and chemically stable, with ample inter-fiber porosity to allow access of reagents for the surface functionalization reaction and, subsequently, for the metal ion's interaction with the ligand. The stability of the attached ligand upon the nanofiber should also be confirmed before use to ensure that the ligand is not leached during application or regeneration by washing in acid or alkaline solution [5]. Thus, the nanofiber adsorbent can then be reused successfully over several cycles, especially during the regeneration of the adsorbent.…”