Membranes - Page 14

Researchers from ETH Zurich and LG Electronics developed a stable porous membrane made from only 2 layers of graphene. They say that this is the thinnest possible porous membrane that is technologically possible to make.

The new membrane can be used as a filter for several different purposes - such as waterproof clothing. In fact the researchers say that their membrane will be a thousand fold more breathable than Goretex! Other applications may include water filteration and gas and liquid flow rate measurements.

Researchers from MIT, Oak Ridge National Laboratory (ORNL) and Saudi Arabia developed a new two-step process that creates subnanoscale pores in graphene. This could enable a cheaper way to create graphene membranes for water purification, desalination and other applications.

The new process starts with a graphene sheet placed on a substrate. The graphene is bombarded with gallium ions, and then etched with an oxidizing solution that reacts strongly with the disrupted carbon bonds and produces a hole (at each spot where the gallium ions hit the graphene). The average size of the hold is determined by how long the graphene sheet is in contact with the oxidizing solution.

Researchers from the University of Pennsylvania developed a new sensitive DNA sensor (sequencer) made from graphene drilled with nanopores. The same team already developed such a sensor in 2010, but this new method increases sequencing speed dramatically.

The idea is that the researchers have now measured current directly from the graphene, whereas before they measured ionic current in the solution as it goes through the pore. The researchers use graphene nanoribbons (GNRs), and when they pass a DNA base through the material, it modules the electrical current - in a different way for each base. The current in this method is a thousand times higher than in the previous method, which means measurements can be done a thousand times faster.

Researchers from Korea's Hanyang University developed new graphene membrane based technology to separate carbon dioxide (CO₂) from nitrogen and hydrogen. This could lead to low-cost greenhouse-gas control systems, and the researchers hope it can be commercialized within two or three years.

The researchers used graphene and graphene oxide based membranes. To create the membranes, the researchers created pores in graphene sheets and then stacked them in such a way that ensured that only CO₂ molecules could go through.

Researchers from India's VIT University combined studied a new hybrid material made from PVC and graphene-oxide (GO). They say that the GO enhances the properties of PVC and makes it useful as battery electrode material, and also for membranes and coating applications.

The researchers combined polyvinyl chloride (PVC) with graphene oxide using the colloidal blending method. The new composites were studied using several methods (including AFM, SEM, TEM and more) and it was found that the GO have been dispersed homogeneously throughout the PVC matrix, and the original research paper includes many measurements and analysis data.

Last week we reported that Graphene Frontiers has been awarded a $744,600 grant from the NSF to develop and scale up their roll-to-roll graphene production. After discussing this with Graphene Frontier's CEO Michael D. Patterson, we have some more information about the company's technology and its business.

Graphene Frontier's technology was developed at the University of Pennsylvania. It is called Atmospheric Pressure CVD, or APCVD. This roll-to-roll process does not need a vacuum so it works in room pressure. The equipment required is smaller, faster and cheaper compared to CVD and this means that the manufacturing will be cost effective.

Researchers from China’s Nanjing University of Aeronautics and Astronautics have been studying graphyne, an allotrope of graphene for desalination applications. They say graphyne is a promising material for this application because it enables high throughput and complete rejection of ions and pollutants. It still requires osmotic pressure though but its energy requirements will be lower than current technologies.

Graphyne is a 2D carbon sheet in which the atoms are connected in a different structure than graphene (some double bonds are replaced with triple bond acetylenic linkages). Graphyne has many nanopores between the atoms that are large enough for water molecules to pass through, but not salt. This means that there's no need to perforate it like is required with graphene and so the researchers theorize that graphyne is more suitable for this application than graphene is.

Bluestone Global Tech decided to open a new European graphene production plant at the University of Manchester. Bluestone will also partner with the University on several projects. Those projects (detailed below) and the pilot production facility are estimated at £5 million ($7.8 million) which will be funded wholly by BGT.

The National Graphene Center plan

This new deal signs the first strategic partnership of the £61 million National Graphene Institute (NGI) established at Manchester and Bluestone is the first company (except University Spin-Offs Graphene Industries and 2-D Tech) to work at the NGI. Specifically Bluestone will open a pre-production facility and will offer graphene material to the University of Manchester's 100+ scientists and engineers working on graphene and other 2D materials. Later on BGT will setup a larger headquarters and a pilot production line at the NGI and will also work towards partnership with other consumer companies.

Researchers from Sweden's KTH (Kungliga Tekniska Högskolan) Royal Institute developed piezoresistive sensors based on graphene membranes. They say that graphene increases the sensitivity of these MEMS sensors by up to 100 times while reducing the thickness.

The researchers used a graphene sheet over a cavity etched into a silicon dioxide (SiO2) film on a silicon substrate. The graphene acts as the membrane. They fabricated a prototype device, in this case a strain gauge, although this technology can be used to make other MEMS based sensors.

American Graphite Technologies (AGT) announced that Cheap Tubes received independent test results for its hybrid bucky/graphene paper formulations and advanced coating technology, and these results confirmed that the materials are conductive, stable and processable on an industrial scale.

Cheap Tubes produced several pre-production quality, highly conductive, flexible and mechanically stable self-supporting membrane samples (made form CNTs and GNPs), refined from mined graphite and other nano components. Cheap Tubes' hybrid paper has a surface area of 116m²/g at 100um thickness, and the company says that it could potentially produce it in sizes up to 36" wide, at speeds up to 50-100 feet of membrane per minute.