Abstract:
Perforated graphene sheets can be used in forming separation membranes. Separation membranes of the present disclosure, which can be used in gas separation processes in some embodiments, can include one or more polymer layers and one or more layers of perforated graphene. Methods for separating a gas mixture can include contacting a gas mixture with the separation membranes, and transiting one or more of the gases through the perforated graphene so as to affect separation.
Abstract:
Provided are nanoporous silicon nitride membranes and methods of making such membranes. The membranes can be part of a monolithic structure or free-standing. The membranes can be made by transfer of the nanoporous structure of a nanoporous silicon or silicon oxide film by, for example, reactive ion etching. The membranes can be used in, for example, filtration applications, hemodialysis applications, hemodialysis devices, laboratory separation devices, multi-well cell culture devices, electronic biosensors, optical biosensors, active pre-concentration filters for microfluidic devices.
Abstract:
Disclosed is a method of manufacturing a partially freestanding two-dimensional crystal film (16, 16'), the method comprising providing a substrate (10) carrying a catalyst layer (14) for forming the two-dimensional crystal layer on a first surface; forming the two-dimensional crystal film on the catalyst layer; covering at least the two-dimensional crystal film with a protective layer (18); etching a cavity (24) in a second surface of the substrate, the second surface being opposite to the first surface, said cavity terminating on the catalyst layer; etching the exposed part of the catalyst layer from the cavity; and removing the protective layer, thereby obtaining a two-dimensional crystal film that is freestanding over said cavity. A device manufactured in this manner is also disclosed.
Abstract:
In a method for forming nanopores, two opposing surfaces of a membrane are exposed to an electrically conducting liquid environment. A nanopore nucleation voltage pulse, having a first nucleation pulse amplitude and duration, is applied between the two membrane surfaces, through the liquid environment. After applying the nanopore nucleation voltage pulse, the electrical conductance of the membrane is measured and compared to a first prespecified electrical conductance. Then at least one additional nanopore nucleation voltage pulse is applied between the two membrane surfaces, through the liquid environment, if the measured electrical conductance is no greater than the first prespecified electrical conductance. At least one nanopore diameter tuning voltage pulse, having a tuning pulse voltage amplitude and duration, is applied between the two membrane surfaces, through the liquid environment, if the measured electrical conductance is greater than the first prespecified electrical conductance and no greater than a second prespecified electrical conductance.
Abstract:
Electrosmotic (EO) pumps which are not subject to mechanical wear and tear and with no moving parts, and having improved flow rates and electrical properties, are described. Atomic layer deposition can be used to prepare two electrical terminal passive zeta potential modulated active EO pumps and novel three electrical terminal active zeta potential modulated EO pumps. First, second, and further thin layers of materials can be introduced into the pores with conformal coating extending from side to side. In the two electrical terminal passive EO pump, the zeta potential of the micropores or nanopores can be controlled by the selection of the material coating the inside walls of the pores. In an three electrical terminal active zeta potential modulated EO pump, the zeta potential can be further controlled by use of an electric field to modulate the zeta potential via an independent third electrode, thereby achieving active control of surface zeta potential using embedded electrode structures within the micropores or nanopores. In addition, coaxial nanostructures, methods for making coaxial nanostructures, and devices incorporating the coaxial nanostructures are disclosed.
Abstract:
Multiple walled nested coaxial nano structures, methods for making multiple walled nested coaxial nanostructures, and devices incorporating the coaxial nanostructures are disclosed. The coaxial nanostructures include an inner nanostructure, a first outer nanotube disposed around the inner nanostructure, and a first annular channel between the inner nanostructure and the first outer nanotube. The coaxial nanostructures have extremely high aspect ratios, ranging from about 5 to about 1,200, or about 300 to about 1200.
Abstract:
The invention relates to a particle detector apparatus for optically ascertaining a number of particles (22) arranged at a surface (20), in particular of a particle filter (14), having a spatially resolving light detector (18), a light source (34), an optical focussing device (32) and an evaluation device (26), which particle detector apparatus is easier to handle than known particle detector apparatuses and the accuracy of which is increased. It is proposed here that the spatially resolving light detector (18) has light sensors (28) which measure brightness values and are preferably designed as at least one integrated circuit, wherein the light detector (18) is designed for producing digital image data from the brightness values supplied by the light sensors (28). The invention furthermore relates to a particle detection method for optically ascertaining a number of particles arranged at a surface (20) of a particle filter (14).
Abstract:
A microfabricated cross flow filter may have multiple filtration stages. The filtration stages may include microfabricated filter barriers and gaps created in a substrate, thereby allowing very tight tolerances in the filter barrier and gap dimensions to be maintained. Using the microfabrication techniques, the filter barriers can be made having arbitrary shapes, and arranged at an angle or curved with respect to the flow direction, making the pressure drop across the filtration stage more uniform in the cross flow direction.
Abstract:
The present invention disclose a method for manufacturing ultra-thin reinforced membranes from a SOI wafer having a front side and a back side, the front side having a etch stop layer buried under a device layer, provided for by forming reinforcement bars by etching openings in the device layer down to the etch stop layer, filling the openings at least partially by deposition of a first filler, and then polishing the top surface to the silicon surface before depositing a membrane material.