Structured nanoporous materials, manufacture of structured nanoporous materials and applications of structured nanoporous materials

A method for manufacturing a structured polymeric material by craze lithography, the method comprising:

• providing a body comprising a precursor polymeric material;
• selectively exposing a first region of the precursor polymeric material to electromagnetic radiation to form a first interference pattern having a characteristic first periodicity;
• selectively exposing a second region of the precursor polymeric material to electromagnetic radiation to form a second interference pattern having a characteristic second periodicity, different to the first periodicity,
• wherein the first and second interference patterns interact with the precursor polymeric material to form a partially cross-linked polymeric material, each interference pattern comprising maxima and minima of intensity of the electromagnetic radiation, the interference patterns thereby causing spatially differential cross linking of the precursor polymeric material to form crosslinked regions having relatively high cross linking density and non-crosslinked regions having relatively low cross linking density, the crosslinked regions and non-crosslinked regions corresponding to the maxima and minima of intensity of the electromagnetic radiation, respectively,
• the method further comprising:
• contacting the partially cross-linked polymeric material with a solvent to cause expansion and crazing of at least some of the non-crosslinked regions to form a stratified porous structure in the first region having a corresponding first stratified porous structure periodicity, and a stratified porous structure in the second region having a corresponding second stratified porous structure periodicity, different to the first stratified porous structure periodicity,
• wherein the solvent used to cause expansion and crazing falls outside a Hansen solubility sphere for the precursor polymeric material when plotted in Hansen space but lies close enough to the Hansen solubility sphere for the precursor polymeric material to expand and craze the precursor polymeric material.