Glass nanofibrous yarn through electrospinning along with in situ synthesis of silver nanoparticles

Among the inorganic nanofibers, silica nanofibers are of great interest due to high reactivity and availability of silicon compounds in nature. Sol–gel process is required for electrospinning of silica nanofibers, in which a metal alkoxide is hydrolyzed and the viscosity increased. In this study, silica nanofibrous yarn containing silver nanoparticles were synthesized and electrospun from a mixture of silica sol with an easy spinnable polymer (PVA) as an additive. The silica sol contains tetraethyl orthosilicate (TEOS), silver nitrate, distilled water, nitric acid and ethanol. Nanofiber yarn was formed through two opposite nozzle methods with the same voltage and diverse polarization. The nanofiber yarn was calcinated to remove the solvent and additive polymer. Consequently, pure silica nanofibrous yarn was produced. FTIR analysis showed entire removal of polyvinyl alcohol from the yarn structure and formation of silan groups. The presence of silver, silica and oxygen was confirmed by EDX and XRD patterns also revealed the presence of silver nanoparticles with a mean crystal size of 18 nm. FESEM images of nanofiber yarn showed the fracture surface on the yarn. Adding silver nitrate into the sol–gel resulted in decrease in nanofiber diameter from 286 to 136 nm. Tensile strength results showed higher strength and modulus of elasticity for the glass nanofiber yarn produced with PVA/sol–gel = 1:4 at 2000 turns per meter (TPM) comparing with other samples by different twist levels and sol–gel ratios. Furthermore, the electrospun glass yarn showed more resistance in acidic media than alkaline media.