Measurement and Modeling of the Nanofiber Surface Potential during Electrospinning on a Patterned Collector: Toward Directed 3D Microstructuration

Electrospinning allows the fabrication of microstructured mats when the nanofiber is deposited on a patterned collector made of regularly distributed protuberances. Such directed self-assembling strategy results from the building of an electrostatic template induced by the charged deposited fiber strands suspended between the protuberances which in turn induces a field of attractive and repulsive forces that guide the deposition of the fiber during its landing. However, after a certain time of electrospinning, the microstructuration of the mat is generally subjected to modification and is eventually lost. Here, it is shown that the measurement of the surface potential above the deposited nanofibers is a powerful tool to track the evolution of the fibrous microstructuration during the fabrication. First, the electrospinning above a single and adjustable gap is deeply investigated and a model is proposed to explain the surface potential kinetics as a function of the gap size and the processed polymer solution. Then, the surface potential kinetics are correlated with the evolution of the 3D microstructuration in the case of electrospinning on a micropatterned collector. This original strategy paves the way for the controlled fabrication of 3D microstructured mats dedicated to a wide range of applications.