During the last two decades, nanofibers have been widely used in biomedicine, industrial wastewater filtration, and water treatment in steel, petrochemical, textile engineering, energy production and storage, biotechnology, heat-resistant materials, and refractories. There are different production methods to make nanofibers, including electrospinning and non-electrospinning methods with different effects on their properties. Electrospinning method is a simple, fast and cost-effective method in addition to its flexibility in producing most polymer fibers with diameters ranging from micrometers to several nanometers. Traditional electrospinning has limitations such as needle clogging, non-uniformity of fibers, use of toxic organic solvents, long processing time and also limitations in non-chemical control of fiber properties. The combination of electrospinning and ultrasonic technique has been used to improve the nanofiber mechanical-physical properties. This research aims to investigating the electrospinning and ultrasonic waves simultaneous combination and the ultrasonic wave effect on nanofiber characteristics. In this device the ultrasonic waves have simultaneously been used with traditional electrospinning device including fluid pumping device and electrospinning power supply. It has been carried out in two main parts. The first part is related to the design and fabrication of the electrospinning-ultrasonic wave device, and the second part is related to investigation of the ultrasonic waves effect on the polyvinyl alcohol polymer production used in wound dressings in various power. In the first step, the design and simulation of electrospinning horn and nozzle have been done and then built. In this structure, the needle, nanofibers collector and polymer movement channel features have significant effect on the device performance. The findings have been shown that the simultaneous combination of the ultrasonic waves and electrospinning cause the needle clogging reduction due to the solution viscosity decrease and the temperature increase due to the local heat increase and particles movements lead to solution evaporation increase and at last the ribbon fibers production. Also, an additional force is applied on the polymer exited because of the ultra frequency oscillation on the needle nose, and the production rate has been increased. After assembling other components of the electrospinning-ultrasonic device, the nanofibers have been produced by the electrospinning power voltage, the needle distance to the collector and ultrasonic waves power changes. The main effective tests in wound dressings production including diameter, the air permeability and elasticity nanofibers have been eva‎luated. It is possible to obtain higher tention, strength, surface-to-volume ratio and higher air permeability nanofibers in different distances and voltages.

امين اله محمدي

مهدي كاروان

محسن صفوي , سعيد ضيائي راد