An apparatus and method for transferring nanofiber structures (e.g., nanofiber films, nanofiber sheets, stacks of nanofiber grids, nanofiber films, nanofiber sheets, and combinations thereof) between various substrates are described. The techniques described use a soluble layer on a substrate that is subsequently dissolved, thus freeing the nanofiber structure from the substrate. This liquid phase techniques preserves the mechanical integrity and the purity of the nanofiber structures.

A tunable nanofiber filter device can include a filter housing defining an interior space, the housing having defined therein and inlet and an outlet, each in fluid communication with the interior space, and a plurality of filter laminas disposed within the interior space, each filter lamina including an upper surface, a lower surface, and an aperture defined therethrough. The plurality of filter laminas can be arranged in a stack wherein the opposing surfaces of adjacent filter laminas define a portion of an interlaminar flow space extending between the opposing surfaces. The flow space can be in fluid communication with the apertures of corresponding adjacent filter laminas to form a continuous flow passage extending through the lamina stack from the inlet to the outlet. An array nanofibers can extend into the flow passage from a portion of each filter lamina such that a fluid flowed through the flow passage flows across a portion of said array.

Filtration membrane comprising polymeric nanofibers and/or microfibers attaching dendrimer component presenting reactive sites selective for chemicals to be filtered, and related nanofibers and microfibers, composite materials, compositions, methods and system.

A filtration membrane comprising cellulose fibres, the membrane having a pore size distribution such that the modal pore diameter is between 10 nm and 25 nm and/or wherein less than 5% of the pore volume comprises pores of greater than 40 nm and having a total porosity greater than 30%.

Membranes are provided for filtering a gas, in some cases air. Membranes using a highly porous cellulose nano fibrous barrier layer with a highly porous (surface-charged) substrate can exhibit high flux, high retention, and low pressure drop in air filtration of toxic aromatic gases, fumes, bacteria, viruses, dusts, and particulate matters.

A tunable nanofiber filter device can include a filter housing defining an interior space, the housing having defined therein and inlet and an outlet, each in fluid communication with the interior space, and a plurality of filter laminas disposed within the interior space, each filter lamina including an upper surface, a lower surface, and an aperture defined therethrough. The plurality of filter laminas can be arranged in a stack wherein the opposing surfaces of adjacent filter laminas define a portion of an interlaminar flow space extending between the opposing surfaces. The flow space can be in fluid communication with the apertures of corresponding adjacent filter laminas to form a continuous flow passage extending through the lamina stack from the inlet to the outlet. An array nanofibers can extend into the flow passage from a portion of each filter lamina such that a fluid flowed through the flow passage flows across a portion of said array.