Many variations in the electrospinning process have emerged to control pore size needed in tissue scaffolds including introducing voids in the collector plate. However, the effect of different shapes and sizes of voids on fiber and pore sizes is not well understood. In this study, we evaluated the effect of void size and shapes in the collector plate on polycaprolactone (PCL) fiber size and pore size. First, we performed experiments using three different sizes of circular voids (0.9, 1.4, and 1.9 cm). Also, we evaluated the effect of triangular and rectangular voids. Further, changes in the electrical field within the voids were evaluated using computational fluid dynamic software COMSOL. Fibers using mixtures of PCL (high, medium, and low molecular weight) formed using void collector plate and performed degradation characteristics for 30 days in physiological conditions (37 degrees C and 7.4 pH). These results showed that the size and the morphology of fibers are not affected by the geometrical patterns of the voids. However, fiber alignment is affected by the void shape due to favorable rearrangement in the electrical field. Fibers can be formed by mixing PCL of different molecular weight, and degradation of PCL fiber was accelerated by the mixture with low molecular weight. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013