Preparation of Polyvinyl Alcohol Fluorescent Nanofiber Mats Modified by Hyperbranched Poly (Phenylalanine-Lysine) via Electrospinning for Metal Ions Detection

Hyperbranched poly (phenylalanine-lysine) (HBPL) is obtained by phenylalanine and lysine and then mixed with Polyvinyl Alcohol (PVA) polymer to electrospin PVA/HBPL fluorescent nanofiber mats (FNM), which is an excellent sensing material for Cu 2+ ions in aqueous solutions. In this work, the relationship between mechanical properties, fluorescent properties and the sensing for Cu 2+ ions of PVA/HBPL FNM are investigated. PVA/HBPL FNM with different mass ratio of PVA and HBPL are characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), fluorescence spectrum and tensile tester. To further improve the water solubility of PVA/HBPL FNM, thermally cross-linking (TCL)-PVA/HBPL FNM is fabricated. The results indicate that the neat PVA FNM couldn’t emit fluorescence under any excitation wavelength, whereas the PVA/HBPL FNM emit blue fluorescence green fluorescence when the irradiation of the excitation wavelength is at 330–385 nm and 450–480 nm, respectively. The tensile strength and Young’s modulus of PVA/HBPL FNM are 8.67 MPa and 342.92 MPa, respectively, which suggested 43.1% and 242.7% than that of neat PVA NM. Furthermore, the solubility rate of TCL-PVA/HBPL FNM is significantly decreased in comparison of FNM in absent of cross-linking. It’s worth noting that TCL-PVA/HBPL FNM possessed higher recognition than other mental ions and could be used as metal ion detection sensor to combine with Cu 2+ . Moreover, it represented a linear relationship between the fluorescence intensity and the concentration of Cu 2+ in the range of 5 µM to 100 µM. The fabricated TCL-PVA/HBPL FNM exhibit high mechanical and fluorescence properties, which make it be potentially envisaged for heavy metal ions detection sensor.