Morphological evolution from porous nanofibers to rice like nanobeans

Polycaprolactone/Polyethylene oxide (PCL/PEO) blends with different morphologies are prepared by electrospinning, and the porous PCL structures are obtained by selective removal of the PEO phase through water treatment. Morphology of the electrospun products evolves from the nanofiber to the rice like nanobeans by controlling the concentration of the blend polymer solution. Nanofiber is obtained at a high solution concentration, and the porosity and diameter of the nanofibers could be tuned by adjusting the PCL content in the blend solution. The needle like materials are present with decreasing solution concentration, and rice like nanobeans are observed with further decrease of the concentration. The decreased macromolecular entanglement is responsible for such morphology evolution.