a method of making a novel composition of a porous medium comprising volume elements of both voids and pores wherein the voids are much larger than the mean size of the pores . the method includes a first step of preparation of a porous medium comprising solid particles the approximate size selected for the voids and pores as volume elements and a second step of removing the particles by etching out with hydrofluoric acid or other means to form a porous medium comprising both voids and pores . in another embodiment , the voids are prepared from bow etching out of a polymeric hydrogel silica particles which were allowed to self - assemble as a crystalline colloidal array prior to formation of the polymeric hydrogel around them , thereby forming a porous medium containing a crystalline colloidal array of voids containing aqueous solution . in another embodiment , a method of partitioning macromolecules between a solution comprising the macromolecules , and the voids and pores of a porous medium . the method includes partitioning of macromolecules between voids , pores and the adjacent solution as used in chromatography , electrophoresis , filtration , extraction , other separation process , drug delivery devices , timed - release devices , and semi - homogeneous catalytic reactors . in another embodiment , a method of using bragg diffraction for detection and monitoring partitioning of macromolecules in the voids comprised in a porous medium comprising a crystalline colloidal array of voids which are much larger than the mean pore size of the medium .