Properties Of PVA/Quercetin Solution And Its Electrostatic Spinning

The solubility of quercetin in ethanol solution was measured by HPLC. The rheological behavior of the solution of PVA and PVA/quercetin in the solution of different concentration of ethanol in water was studied by a rheometer RV2. The nanofiber of PVA/quercetin was made by the gas-jet/electrostatic spinning. The diameters of PVA/quercetin nanofibers were from 200nm to 450nm. The controlled release of the film of PVA/quercetin in simulated body fluid (SBF) was also studied. Quercetin is insoluble in water, but it is soluble in ethanol. The solubility of quercetin in ethanol was measured in the equilibrium method by HPLC in this work. The influence of temperature on the solubility was studied, and the solubility increased as temperature increased. The solubility and related physical property was correlated and discussed, and the experiential formula of solubility was obtained. The suggested value of solubility was calculated by experiential formula. It provided theoretical reference for the preparation of solution. The rheological behavior of the solution of PVA and PVA/quercetin in ethanol/water was studied by a rheometer RV2. As well known, PVA is water-solubility polymer. When the water solution of PVA is added by a little ethanol, PVA will not be precipitated. But when the ethanol is exceeded by a certain percent, the PVA will be precipitated. PVA with the degree of polymerization of 1799 was used in the paper, and the percent of ethanol was not exceeded by 40%. The experimental results show that the rheological behavior of PVA solution was similar to Newtonian fluid under experimental shear speed, and the non-Newtonian behavior was obvious when an amount of quercetin was added. The viscosity was related with the concentrations of PVA and quercetin, the ration ethanol to water, and the temperature of solution. High concentration of PVA, content of quercetin, the ration ethanol to water and low temperature all increased the solution viscosity. The nanofibers of PVA/quercetin were made by gas-jet/electrostatic spinning. The morphology and diameter of nanofibers were analyzed by SEM. It was shown in experimental results that the key factors influencing the diameter of nanofibers were the applied voltages, the concentrations of PVA solution and the distances between the spinneret and the collector. The diameter of nanofibers was getting smaller as applied voltages and the distances between the spinneret and the collector were increasing, and the concentrations of PVA solution was decreasing. The suitable technology of nanofibers depends on the rheological properties of the spinning fluid. When the viscosity was 0.66 Pa·s, the obtained nanofibers were good, with small diameters and without beads. Both higher and lower viscosities were unsuitable for the spinning. Higher viscosity could produce the solution gel, which makes the difficulty of spinning. Lower viscosity will form beads. The film of PVA/quercetin was made and controlled release in SBF was studied. The results were analyzed by thin layer chromatography. The bright dot was observed in ultraviolet light. The result of contrast shows that quercetin could be controlled release in SBF.