directed to the preparation of electrospun fibers from difficult to process fluids and of fibers with smaller diameters and core shell structure the process utilizes an electrospinneret as shown in fig1 and 2 that allows for co axial extrusion of two fluids the housing of the electrospinneret 10 consists of a concentric inner tube 12 and outer tube 14 by which two fluids are introduced to the spinneret one hereafter denoted the u201c core fluid u201d in the core of the inner tube 12 and the other hereafter denoted the u201c shell fluid u201d in the annular space between the inner tube 12 and the outer tube 14 the electro spinneret is designed to keep the fluids separate as they are charged via a high energy source 16 and emitted from a nozzle 20 the materials of construction are chosen such that either one or both of the fluids may be charged by contact with a high voltage as the fluid passes through the spinneret in the examples below the spinneret shown in fig2 was used in a parallel plate equipment configuration the spinneret has two generally steel tubes so that both fluids were charged simultaneously to the same potential in the specific device shown the inner tube 12 having an i.