Electrospinning of hydroxypropyl methylcellulose trimellitate solutions

Nonwoven fiber mats of hydroxypropyl methylcellulose trimellitate (HPMCT) with potential applications in controlled delivery of drugs and scaffolds for tissue cultures have been successfully fabricated by electrospinning of HPMCT solutions. The formation and diameters of HPMCT fibers fabricated by electrospinning were strongly influenced by the solvents employed, electrostatic field strength, and solution concentrations. The electrospun products generated from all HPMCT solutions with various weight-average molecular weights in methanol/dichloromethane (1:1) solvent consisted of clustered beads, while methanol/dichloromethane (1:5) solvent helped to generate smooth, uniform, submicron fibers. From the relationship between specific viscosity and molecular weight in different solvents, it could be concluded that methanol/ dichloromethane (1:5) solvent enhanced the molecular entanglements, improved the viscosity of the solutions, thus helped to generate smooth fibers. When all the other variables were kept constant, the concentration range suitable for electrospinning was between 10% and 16% (wt), and the average fiber diameter increased as the concentration increased. When all the other variables were kept constant, the average fiber diameter decreased as the strength of the electrostatic field increased. Electrospinning the solutions of two compounds with similar structure, hydroxypropyl methylcellulose phthalate (HPMCP) and HPMCT, we found that the fibers electrospun from HPMCP were thicker than that from HPMCT, which is attributed to the fact that the solution's conductivity of HPMCT (containing two free carboxyl groups) is higher than that of HPMCP (containing only one free carboxyl group).