{HEAD ~ A chemically modified membrane} is positioned between a first template having a first set of holes and {TAIL ~ a second set} of holes aligned with the first set of holes to define a plurality of exposed portions of the membrane in such as manner as to prevent collapse of pores in the membrane during application of a differential pressure across the membrane 
{ HEAD ~ A chemically modified membrane } is positioned between a first template having a first set of holes and { TAIL ~ a second set } of holes aligned with the first set of holes to define a plurality of exposed portions of the membrane in such as manner as to prevent collapse of pores in the membrane during application of a differential pressure across the membrane
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH