Nano News: 03/16/15

Parallel scanning probe microscope beats single scanning 1000 fold

TNO, an independent research organization in The Netherlands, has developed a multiple miniaturized Scanning Probe Microscopy (MSPM) heads system, which can inspect and measure many sites in parallel. This system means an enhancement of throughput in order of more than 1000 times the single SPM throughput. It is capable of more than 10 wafers per hour throughput in Semicon and nanoelectronics industry and parallel and simultaneous measurement of biomedical samples to guarantee the same condition of scanning for all samples. Because of the speed and parallel scanning, the conditions during measurement are less likely to change due to variation in temperature, bio process. This has many advantages e.g. if used for statistical analysis.

Picture of one of the demonstration arm which carries one miniaturized SPM head. (Image: TNO) (click on image to enlarge) (SPM) is emerging as an essential nanoinstrument in many applications where nanometer resolution imaging and characterization are required. The ability to accurately measure critical dimensions in nanometer scale, has made it an important instrument in several industrial applications such as semiconductor, solar, data storage, bio-medical, pharma and food science. Examples of applications are surface roughness, channel height and width measurement, defect inspection in wafers, masks and flat panel displays. In most of these applications, the target area is very large, and, therefore, the throughput of the measurement plays an important role in the final production cost. Single SPM has never been able to compete with other inspection systems in throughput, thus has not fulfilled the industry needs in throughput and cost. Further increase of the speed of the single SPM helps, but it still is far from the required throughput and, therefore, insufficient for high-volume manufacturing.

Illustration of parallel SPM to image several locations on a wafer or mask. Multiple positioning arms on two sides of the wafer stage, each capable of moving a miniaturised SPM scan head on to a large sample. Many parallel miniaturised SPM heads enable full area coverage at high throughput. (Image: TNO) Over the past few years, within the Enabling Technology Program (ETP) Optomechatronics at TNO a revolutionary architecture for a multiple miniaturized SPM (MSPM) heads system has been developed, which can inspect and measure many sites in parallel. The very high speed of miniaturized SPM heads allow the user to scan many area, each with the size of tens of micrometers, in few seconds. Recent experimental results has convinced that the time for a parallel SPM has arrived. This research line has led to over 10 internationally granted patents and several scientific publications in journals and on conferences. One of them was awarded as second best paper at the EMLC 2014 conference.

Research proves single wall carbon nanotubes capable of significantly improving elastomer properties

The rapidly developing rubber industry is facing on increasing growth in property requirements, from increases in elasticity, strength, and resistance to aggressive environments, weatherability and many others. Many of these improvements will require a complex of new materials and technology. Some of these targets, however, can be reached by combining a rubber blend with single wall carbon nanotubes. A third party has researched the influence TUBALL-branded single wall carbon nanotubes have on elastomers. Recent results have demonstrated the positive impact single wall carbon nanotubes can make to the physical, mechanical and chemical indexes of elastomer composites. To start with, increasing the concentration of single wall carbon nanotubes in the elastomer composite blend improves tensile strength and reduces tensile elongation. In parallel, the hardness of the blend increases, which is proved by Shore A test results. These strength improvements also indicate a good distribution of single wall carbon nanotubes in the material. Therefore, the ultimate strength of the composite is higher, and enabling it to withstand heavier mechanical loads than the control blend. Additionally, increasing the concentration of single wall carbon nanotubes in the composite lowers residual deformation under compression. Thus, it can be presumed, that the blend with such a composition will perform better when subjected to permanent and variable deformation after adding the single wall carbon nanotube modifier. This allows for the additive to be viable for producing a number of elastomer products, including seals, compactors and other mechanical rubber goods. Another added effect is also that electrical resistance of the blend is reduced. This may be used to improve a number of elastomer products, such as electrodes, electrical current conductors, electrical and radiotechnical devices, coatings for charger units and batteries, and so on. One downside to increased nanotube concentration is that composite viscosity also increases, which raises the processing power required.

Composite electrical resistance change. Higher concentrations of nanotubes also significantly shortened the start time of vulcanization and notably speeded it up. Though the blend’s viscosity increased, this change was insignificant, and it did not influence energy consumption on production. Noteworthy, higher vulcanization speed can be also a consequence of existing functional groups, meaning single wall carbon nanotubes don’t just organize their own 3D matrix but also chemically interreact with the composite matrix in process of vulcanization. Higher vulcanization pace also increases the speed of material processing, which means it requires less time to produce one product unit. However, the possibility of early vulcanization for large products should be kept in mind. This will require additional research to obtain more clarity on the matter. While testing the abrasion of samples, the loss indicator of the testing composites decreased and resistance to abrasion went up after increasing the concentration of nanotubes in the blend. It must be noted that increasing the strength by just 10% decreased abrasion by 15%, which is a significant improvement. Products based on this composition will be more wear-resistant when exposed to frictional forces, which is one of the priority goals while producing conveyor belts, automobile tires and other goods subject to such loads. As for glass transition temperature, research results demonstrated an increase within the limits of experimental error. Increasing elasticity modulus under all testing temperatures indicated that single wall carbon nanotubes positively influenced the mechanical properties of the material, with minor changes in the mechanical loss factor. With higher concentrations of nanotubes, a lower tan δ at 60°C demonstrated a decrease in the rubber blend’s hysteresis loss. Except for the maximum concentration of added nanotubes, where can be noticed the leap. Therefore, at 60°C many deformations will have a bigger influence on rubber fatigue with maximum concentration than with any other. Young’s modulus changes were insignificant, except for the highest concentration of nanotubes. The latter case demonstrated a significant change: it required much more effort to deform the sample. This means that materials with the maximum practical concentration of single wall carbon nanotubes will have greater durability, within the range of testing temperatures (-10 — 60°C). One additional positive factor is the minor change of tan δ at 0 °C that defines wet road grip.

Viscoelasticity properties. All property improvements mentioned above demonstrate that adding single wall carbon nanotubes to rubber blends improves strength characteristics, abrasion, hysteresis loss, elasticity, vulcanization speed and residual deformation under compression. The practical explanation for these improvements is that nanotubes of this kind organize their own dimension network embedded in the composite matrix: electrical resistance decline proves this along with physical and mechanical testing data. Regarding the best concentration option: the research results defined it to be 0.2% — this being the optimally observed amount to improve material properties

Developing a photocatalytic raector to treat agricultural wastewaters

PCATDES is an ambitious collaborative project between the European Union of South East Asian Nations (ASEAN), financially supported by the European Commission under its Seventh Framework Programme, grant number 309846. The PCATDES Project combines 11 cross disciplinary teams from 7 ASEAN and EU countries. The consortium is focused on developing a cost effective, prototype photo-catalytic reactor with the capability of helping the agricultural and fisheries industries, based in less well developed and more remote areas, to clean and recycle waste water left over after current industrial and biological processes have been applied. The Project has been set the challenge of developing novel catalytic materials alongside new photo catalytic processes with the potential to assist target industries improve their waste water management. The PCATDES project reached the mid-point of its 4 year period in January 2015 and an Annual Review Meeting was held in Istanbul on 15th and 16th February 2015. The meeting allowed Partners to: demonstrate progress; discuss technical matters face to face; consider management issues and plan for a successful outcome in 2017. 10 out of 11 Partners were able to attend the meeting, with representatives from the universities of Aston, Bath, Cardiff and UCL in the UK, and from the universities of Rey Juan Carlos and Rostock (Spain and Germany respectively). From the ASEAN countries representatives came from the Vietnam Academy of Science & Tech; SIRIM-Berhad (Malaysia); National Metal & Materials Technology Centre (Thailand). The meeting was hosted by Sampas Nanotechnology an SME, based in Istanbul. Dr Silvia Gross also attended the meeting in her capacity as the Project’s EC Technical Officer. The meeting heard that good progress is being made against the PCATDES work plan. URJC has built and fully characterised a prototype reactor, incorporating a light sources consisting of ultra-violet LEDs developed by Bath. The reactor is now in operation in the laboratories of 10 out of the 11 partners. Novel catalytic materials have been created along with catalytic structures and coatings and kinetic and mechanistic studies are also underway. Project Coordinators, Cardiff University and Aston University, are pleased with not only the scientific progress but also the positive collaboration involving partners spread around the globe. Sampas Nanotechnology, Turkey is responsible for business planning; dissemination and potential IPR and future exploitation resulting from the project and business invited a Turkish Olive Oil Producer, Mr Bugra Onal to present to the meeting on the waste water challenges facing his Industry. There is a striking similarity between the issues faced in Turkey, Greece and Spain with olive oil production and those encountered by palm oil producers in Malaysia and Fisheries in Vietnam. Looking forward, the PCATDES project has to consider the design, including lighting, of a scaled up reactor that will be built and deployed in Malaysia. This decision will also see the project choose the best, cost effective catalysts; coatings and architecture. The PCATDES Project looks forward to testing a scaled up photo catalytic reactor in the ‘Field’. However, its chance of success is dependent on many factors outside of its control, such as, Government legislation; industrial practices and the effectiveness (or otherwise) of current systems to clean the water of sufficient contaminants before photo catalysis is applied.