Polymeric microsieves via phase separation microfabrication: Process and design optimization

Phase separation microfabrication (PSμF) is a fabrication method that allows the preparation of membranes having micropattern surface topologies. PSμF has been successfully used for manufacturing polymeric microsieves. The technique benefits from the vertical shrinkage of polymer solutions to ensure perforation by the pillars on the mold. The horizontal shrinkage causes deformation of some pores and increased peeling forces. This can lead to rupture of molds as well as inoperable microsieves. The effect of several parameters of mold design as well as peeling orientation is addressed. A peeling device equipped with a force transducer is used to measure the force required for peeling in each case. Peeling forces decrease with lower pillar densities, the use of alternative geometries for the pillars (i.e. not round pillars) and the use of alternative pillar placing (i.e. not square pitch).