ANALYSIS OF ELECTROSPINNING NANOFIBERS: DIAMETER DISTRIBUTION, PROCESS DYNAMICS, AND CONTROL

Electrospinning is a method of producing nanometer scale fibers by accelerating a jet of charged polymer solution in an electric field. In many emerging, high value electrospinning applications, such as the biomedical area, the diameter distribution of electrospun polymeric nanofibers has important implications for the product's performance and process economics (in terms of yield and production rate). However, the current state-of-the-art electrospinning process results in unpredictable and time varying diameter distributions, both during a run and run-to-run. Thus, this work is focused on developing an appropriate control system to achieve consistent and controllable fiber diameters. Another goal of this work is to develop a better understanding of the relation between process physics and the resulting fiber diameter characteristics. To address these problems, a well instrumented and computer based actuator control system has been developed. The effects of process parameters on fiber diameter are investigated for achieving consistent and repeatable process capability. The fundamental process dynamics are identified and the relation between measurable variables and the resulting fiber diameter distribution is analyzed. This relation provides the basis of developing appropriate control strategies in order to reduce both the process variations from run-to-run and during a run.