Surface morphology and mechanical response of randomly oriented electrospun nanofibrous membrane

Electrospinning for the fabrication of fibrous membranes has received great attention due to the simplicity of the technique, ability to effectively control the process and potential for production scale-up. While the optimization of electrospinning parameters for various polymers is widely investigated, the mechanical characterization and modeling of the mechanical response of electrospun membranes remain a major challenge. The present work focuses on the mechanical characterization of electrospun nanofibrous membrane under simple and complex loading conditions. For this purpose, polyvinylidene fluoride (PVDF) is considered for the membrane material. Three types of uniaxial mechanical tests are conducted: monotonic tensile test, cyclic loading test with increasing maximum strain and cyclic-relaxation test. The evolution of fiber re-orientation with deformation is also investigated. Results show that the membrane is initially isotropic in the plane. Moreover, the evolution of membrane Young's modulus with increasing maximum strain suggests that mechanical deformation induces two interacting phenomena: fiber re-orientation and inter-fiber bond damage.