Abstract: A process of producing a structure for molecular separations includes providing a plurality of template materials. The template materials are selected from biomolecules, biopolymers, polymers, or combinations thereof. A sieve material, suitable for producing a structure for molecular separations, is provided around the template materials. The template materials are positioned in an arrangement for leaving pores suitable for molecular separations. The template materials are removed to leave pores in the sieve material and produce the structure suitable for molecular separations.