Identifying key processing parameters for the electrospinning of aligned polymer nanofibers

• Systematic study of fiber alignment in electrospinning carried out.
• Using a rotating collector leads to aligned electrospun polycaprolactone fibers.
• Fiber alignment was independent of collector rotation velocity.
• Fiber collection efficiency improved by increasing velocity above critical value.

Aligned polycaprolactone (PCL) fibers of interest for numerous applications requiring contact guidance and textured topography were fabricated by electrospinning onto a rotating collector using tangential velocities ranging from 0 m/s to 11 m/s. The deposition characteristics of the fibers were investigated by microscopic methods to gather information about fiber diameter, collection angle θ, and number of fibers per reference length. It was shown that the deposition angle ranged from −2.0° to 1.6° and the diameter of the developed fibers averaged 587 nm to 878 nm. Furthermore the deposition angle was found to be independent of the rotation velocity. Homogeneity of the fiber mats was improved with increasing rotation velocity. The number of fibers per reference length, a measure for collection efficiency, proved to be dependent on the rotation velocity, following a modified Weibull function. Hence the collection efficiency of the process can be improved by increasing the rotation velocity above a critical value.