Tailoring electrospun polymer blend carriers for nutrient delivery in seed coating for sustainable agriculture

The fabrication of ultrathin fibrous seed coating material with focus on improving the germination potential of the seed was the aim of this work. In this effort, we have fabricated electrospun Polyvinylpyrrolidone (PVP) - poly (diethoxy) phosphazene (PPZ) nanofibers. PVP is biocompatible, biodegradable and a commonly used seed coating material while PPZ is a nitrogen and phosphorus rich, hydrophobic polymer which undergoes 74% degradation in 12 weeks. Cowpea (Vigna unguiculata) seeds with a harvesting time of 90 days were used as test subject. Electrospinning confers water permeability, gaseous exchange and does not have residual solvent which is an advantage over film coats. The fabricated blends were characterised by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) etc and it showed partial compatibility of the polymers. The phase contrast microscopic images also showed two phases. A decrease in wettability with increase in the PPZ content in the fibers was seen from water contact angle measurements. The swelling and stability studies indicated that the presence of PPZ in the fibers helps retention of material on the seed. The seed viability and the degradation of the fibrous seed coating were studied using conductivity meter and pH meter. The observed experimental findings may be beneficial and of prospective use in sustainable agriculture. Such polymer blends have the potential to reduce water and soil pollution as well as protect the seed during storage and increase crop yield. (C) 2017 Elsevier Ltd. All rights reserved.