The present article describes the modeling and simulation of the dynamics of the electrospinning process coupled with the spatio-temporal evolution of fiber morphology driven by concentration sweeps. The electrospinning process has been modeled based on an array of beads connected by Maxwell's elements in a cylindrical shell to describe the force balance between Coulombic and viscoelastic forces at the surface of the jet. The phase separation dynamics has been calculated in the framework of the Cahn-Hilliard time-evolution equation by incorporating Flory-Huggins free energy for liquid-liquid demixing in conjunction with solvent evaporation through the fiber surface. The simulations based on the coupling of these two processes have revealed in situ morphology development registering all structural forming processes such as polymer droplets, interconnected spinodal structure, and the porous structure along the spinline. The simulated porous fiber shows a striking resemblance to the experimental finding. (C) 2007 American Institute of Physics.