A membrane includes a plurality of nanopores, each nanopore including a first opening on a first side of the membrane, a second opening on a second side of the membrane, and an inner surface that extends between the first and second openings, wherein at least one nanopore comprises a positive surface charge zone extending along a portion of a length of the nanopore and a negative surface charge zone extending along a different portion of the length of the nanopore, wherein the inner surface of the nanopore has high-density positive surface charges within the positive surface charge zone and high-density negative surface charges within the negative surface charge zone.

A system for manufacturing a membrane filter is provided. The system includes a radiation source operative to emit radiation that contacts discrete portions of a filter substrate so as to facilitate the formation of openings within the filter substrate, and a collimator disposed between the filter substrate and the radiation source and operative to restrict some of the radiation from contacting the filter substrate.

Porous liquid-filtering membranes are provided having a boundary region substantially surrounding the pore region and having greater tear resistance than the pore region.

It can be difficult to remove atomically thin films, such as graphene, graphene-based material and other two-dimensional materials, from a growth substrate and then to transfer the thin films to a secondary substrate. Tearing and conformality issues can arise during the removal and transfer processes. Processes for forming a composite structure by manipulating a two-dimensional material, such as graphene or graphene-base material, can include: providing a two-dimensional material adhered to a growth substrate; depositing a supporting layer on the two-dimensional material while the two-dimensional material is adhered to the growth substrate; and releasing the two-dimensional material from the growth substrate, the two-dimensional material remaining in contact with the supporting layer following release of the two-dimensional material from the growth substrate.

Porous liquid-filtering membranes are provided having a boundary region substantially surrounding the pore region and having greater tear resistance than the pore region.

An object of the present invention is to provide a resin membrane filter having excellent separation accuracy and excellent toughness, and a manufacturing method of the resin membrane filter.

The resin membrane filter of the present invention includes a first main surface, a second main surface, and a plurality of through-holes, in which, in the through-hole, in a case where an average area of an opening portion at a position A which is located at a distance of 10% of a thickness of the resin membrane filter from the first main surface is denoted as Sva and an average area of an opening portion at a position B which is located at a distance of 90% of the thickness of the resin membrane filter from the first main surface is denoted as Svb, 0.8?Sva/Svb?1.25, a number ratio Ra of through-holes in which an area of the opening portion at the position A is more than 1.25 times Sva is 3.0% or less, and a number ratio Rb of through-holes in which an area of the opening portion at the position B is more than 1.25 times Svb is 3.0% or less.

Micro- and nanofilters with precision pore sizes and pore layout have applications in many fields including capturing circulating tumor cells and fetal cells in blood, water treatment, pathogen detection in water, etc. Methods to fabricate micro- and nanofilters not using track etching or reactive ion etching are provided, allowing easy fabrication of single layer or stack of films simultaneously, and/or stack of films on rolls. Microfilter can be made using one or more layers of material. Invention enables mass production of microfilters with lithographic quality at low cost. Isolation, enumeration and characterization of circulating tumor cells using microfilters provides (i) guides to cancer treatment selection and personalize dosage, (ii) low cost monitoring for treatment response, disease progression and recurrence, (iii) assessment of pharmacodynamic effects, (iv) information on mechanisms of resistance to therapy, and (v) cancer staging. Microfabrication methods are also applicable to fabrication of any free standing patterned polymeric films.

Hierarchical porous membranes suitable for use in oil/water separation processes are provided. The membranes described herein are particularly well suited for separating trace amounts of water (e.g., no greater than 3 wt % water content, no greater than 1 wt % water content, or 50-1000 ppm water) from oil. The membranes have a wide range of applications, including deep seep oil exploration, oil purification, and oil spill cleanup.

The present invention relates to a method for preparing a free-standing polymer film with micropores in a simple and economical way, and particularly to a method for preparing a free-standing polymer film with micropores that includes: (a) forming a thin film of a water-soluble polymer on a substrate; (b) forming a thin film of a hydrophobic polymer on the water-soluble polymer thin film; (c) treating the substrate having the polymer thin films formed on with a mixed solution of a solvent and a C1-C3 alcohol and drying the substrate; and (d) immersing the dried substrate in water to dissolve the water-soluble polymer thin film and thereby to peel the hydrophobic polymer thin film from the substrate.

A system for manufacturing a membrane filter is provided. The system includes a radiation source operative to emit radiation that contacts discrete portions of a filter substrate so as to facilitate the formation of openings within the filter substrate, and a collimator disposed between the filter substrate and the radiation source and operative to restrict some of the radiation from contacting the filter substrate.