2.1. Needleless electrospinning of PLA nano-fibrous membrane

The polymer solution was prepared by dissolving 15 wt% of premium quality PLA polymer beads in dichloromethane (DCM) solvent. Dissolution of the PLA polymer was carried out at room temperature in the presence of continuous magnetic stirring at 200 rpm speed. Traditional Indian herbal extracts of Azadirachta Indica (10 wt% with respect to PLA) and Eucalyptus Citriodora (10 wt% with respect to PLA) were added to the polymer solution and mixed thoroughly to achieve a homogeneous solution. Viscosity of polymer solution was analyzed using a Brookfield Viscometer to determine the spinning characteristics of polymer solution. The polymer solution was then subjected to needleless electrospinning using the pilot scale plant machine i.e. Model: Nanospider^TM Make: Elmarco s.r.o., Czech Republic, at Ahmedabad Textile Industry’s Research Association (ATIRA) (as per assembly in Fig. 1 ). In the needleless electrospinning assembly, the distance between two electrodes was fixed at 18 cm for obtaining a nano-fibrous layer. Voltage at the collector electrode was adjusted to −30 kV, whereas the rotating electrode voltage was maintained at 60 kV for facilitating the effective formation of nano-fibers. The rotating electrode speed was fixed at 6 rpm for deposition of a nano-fibrous layer on base cotton fabric at the collector terminal. Cotton fabric at the collector electrode was processed at a speed of 0.5 m/min, 1 m/min, 2 m/min, and 3 m/min for depositing the nano-fibrous layer. An optimum closely packed nano-fibrous layer was achieved at the collector electrode speed of 1 m/min. The optimization of collector processing time was carried out by measuring thickness of nano-fiber layer on base cotton fabric using a digital thickness meter gauge.

Assembly for needleless electrospinning of polymer solution.