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Multiphysics modeling of the electrospinning process
Continuous nanofibers represent an emerging new class of nanomaterials with dual nano- and macro-features that attracts rapidly growing interest due to its critical advantages for a broad range of nanotechnology applications. Electrospinning is a process producing ultrafine continuous nanofibers by jetting polymer solutions in high electric fields. Fine, electrically driven jets emanate from a polymer solution bath, get accelerated and stretched by the external electric field, experience electrohydrodynamic instabilities, and get deposited on substrates in the form of nanofiber mats or arrays. Despite substantial effort in the last decade, many features of this complex process are not yet fully understood. One such feature is solvent evaporation. Previous studies in our group at UNL as well as studies by others have treated electrospun jets as a coupled electromechanical process. Three-dimensional (3D) jet flow was reduced to one-dimensional (1D) by averaging over the jet cross-section. At the same time, solvent evaporation is expected to lead to substantial inhomogeneity over both jet cross-section and length. Solvent evaporation from the ultrafine jets occurs during jet flight and results in the deposition of nearly dry nanofibers on the substrate. Evaporation may have substantial effect on the jet motion in electrospinning and has to be taken into account in process analysis. The main objective of this dissertation was to develop a first comprehensive coupled 3D model of electrospun jets incorporating solvent evaporation and to study effects of evaporation on jet motion and nanofiber formation. The results show complex interdependence of different physical phenomena in the electrospun jets and demonstrate the need for 3D coupled modeling. The developed model and new insights gained in this work will have an impact on control and optimization of nanofiber formation in the electrospinning process.^
Applied Mechanics|Engineering, General|Nanotechnology
Salkovskiy, Yury, "Multiphysics modeling of the electrospinning process" (2011). ETD collection for University of Nebraska - Lincoln. AAI3487267.