nanomaterials news - University of Kentucky · 2010. 1. 21. · (nano-free) to yellow (may contain...

used in many critical and growing sectors in a very short period of timersquo

Paper could form basis of batteries

It may look like a sheet of black paper but a composite

material developed by scientists at the Rensselaer Polytechnic Institute in New York could form the basis of batteries that power tomorrowrsquos consumer gadgets and medical implants The paper could also be used in vehicles with the material built into the chassis structure

Formed from nanoporous cellulose paper infused with carbon nanotube electrodes the devices built by Robert

Linhardt and his colleagues can function as both lithium-ion cells and supercapacitors that provide quick bursts of electrical energy Being flexible they can be rolled twisted folded and cut into various shapes and their thinness allows the sheets to be stacked like reams of paper

The electrolyte is an ionic liquid containing no water and the batteries can withstand temperatures from -70 to +150degC Natural electrolytes such as human blood sweat and urine can also be used in which case the cells could be used to

Cont on page 2 444

Silicon Valley-based Cnano

Technology a company that focuses on carbon nanotube development production and applications recently received $6 million (euro44 million) in venture capital to further develop and exploit its patented nanotube manufacturing process

With support from CMEA

Ventures Pangaea Ventures and WI Harper Cnano aims to enable the rapid large-scale application of carbon nanotubes in many industries The company claims that several corporations are currently evaluating its products and expects recent developments to lead to rapid market penetration

Cnanorsquos president and CEO Xindi Wu explains that the core of the companyrsquos production process is no different from others lsquoHowever our growth system and combination of catalysts and growth parameters are very differentrsquo he says lsquoWe leverage existing mass-production approaches instead of scaling laboratory processesrsquo

Wu adds that the production process is very scalable and that unit costs

will go down very quickly as production volumes rise lsquoOur cost should be much lower than any existing technologies and processesrsquo Actual production is carried out in China which will no doubt have an impact on Cnanorsquos competitiveness in the global marketplace

Cnano focuses mainly on producing multi-walled nanotubes with diameters of between 10 and 30nm It also produces entangled double-walled nanotubes with diameters of 1ndash2nm and vertically-aligned multi-walled nanotubes with controllable lengths of up to 5mm Purity levels are over 90 for multi-walled nanotubes The company also provides services for special additive technologies dispersion and compounding solutions

lsquoThere are relatively few companies today that can bring significant transformational science and technology to a broad set of industriesrsquo said Tom Baruch of CMEA Ventures and chairman of Cnano lsquoCnano has the potential to meet the cost and performance specifications required to enable its advanced material products to be

Vol Three Issue Thirteen 4 September 2007

copyCopyright Pira International Ltd 2007

Cnano wins $6 million to develop low-cost carbon nanotube manufacturing process

In this issue

Automation of Page 2 nanotech with CAD Sensing skin could Page 3 reveal cracks in bridges Nanoscale blasting Page 3 improves sensors Friends of the Earth Page 4 avoids nano sunscreen QampA Page 5 EPAndashtoolittletoolate Ionic wind could cool Page 6 future computers Mass production of Page 6 nanogap electrodes Self-assembly of Page 7 conductive nanowires

Nanoengineered inks and pigments

27mdash28 September 2007 Doubletree Hotel Avenue of

the Arts Philadelphia PA

Click here to find out more

nanomaterials news

Researchers at Duke University in North

Carolina US have adapted an established design and manufacturing process to reproduce structures with single molecule-sized features The development could help make the industrial scale fabrication of nanoscale devices feasible while capitalising on skills possessed by todayrsquos engineering workforce

Using the computing language of macroscale milling machines to guide the tip of an atomic force microscope (AFM) the system devised by Matthew Johannes Daniel Cole and

(computer numerical control) machining to articulate the microscope

probe in two dimensions They then vary the voltage applied to the probe using information stored in the third dimension of a computer-aided design drawing and this provides control over feature height on the surface

lsquoThe technique will allow others to build ldquoprototyperdquo devices in laboratories that will enable basic research with equipment that is relatively cost effectiversquo says Lynch lsquoOur primary objective is to provide researchers with enabling tools that will accelerate the development phase of nanotechnology

lsquoThe research efforts at Duke illustrate the effectiveness of innovative ideas on ways to combine naturersquos tools for replication with the power of employing engineering tools to automate the

Automation of nanotech manufacturing with computer-aided design


02Vol Three Issue Thirteen 4 September 2007

Robert Clark can reproduce three-dimensional silicon oxide nanostructures through a process known as anodisation nanolithography

In this process oxides are built up on semiconductor and metal surfaces by applying an electric field in the presence of trace amounts of water An advantage of using an AFM is that the structures can be visualised as they are being made

What Clark and his colleagues have done is to implement 3-D control of the deposition process through the use of so-called lsquog-codersquo from CNC

nanomaterials news

444 Cont from page 1

power heart pacemakers and other medical devices

lsquoCellulose is very stable towards mammalian enzymes and under physiological conditionsrsquo says Linhardt

lsquoCellulose is also relatively biocompatible Other medical uses of our paper super- capacitor might be as disposable defibrillatorsrsquo

Medical applications will take some time to realise and Linhardt sees supercapacitors as

Battery made from cellulose paper with aligned carbon nanotubes

Source Victor PushparajRensselaer Polytechnic Institute

the first commercial development of the storage devices lsquoThe power storage density is comparable with current devices on the market and they are flexible and have a high range of operating temperaturesrsquo he says

The researchers have yet to develop a way of inexpensively mass-producing the paper batteries and capacitors but the goal is film casting and roll-to-roll printing They are also looking at boosting the efficiency of the devices

lsquoI think this is a novel idea with great potentialrsquo says MIT chemical engineer Robert

Langer lsquoIt could be a very important advance in the energy storage arearsquo

Click here for more informationabout the research

Three-dimensional design and replication of silicon oxide nanostructures using an atomic force microscope

Source Johannes et al Nanotechnology 18 345304 (2007)

processrsquo says Kevin Lyons a manufacturing engineer at the National Institute of Standards and Technology in Gaithersburg US lsquoThis hits dead-on the goal of defining new processes that will set the stage for the next industrial revolution in nano-manufacturingrsquo

Sensing skin could reveal cracks in bridges

A new sensing skin for bridges buildings and

aeroplanes developed by engineers at the University

of Michigan could prevent disasters similar to the recent bridge collapse in Minneapolis

Bridges undergo regular testing for cracks corrosion and other damage but even rigorous visual inspection might not catch all potential problems The ideal would be for materials with built-in sensors that alert testers to structural changes well before

they become a problemTsung-Chin Hou Kenneth Loh

and research leader Jerome

Lynch have taken a step toward this ideal by developing a sensing skin made from thin polymer films embedded with carbon nanotubes Each layer can be configured to measure a single parameter such as acidity or pressure and by measuring changes in electrical resistance when a current is passed through the skin one can generate a two-dimensional structural map of

the underlying materialThe films are assembled using

a layer-by-layer (LBL) process and mounted with electrodes along the boundaries Coatings could in theory be sprayed or painted onto surfaces but with LBL the electrodes can be included in the skin design

lsquoThe sensors are fairly durable mechanically but they still need to be tested in the field where they will be exposed to harsh weather conditionsrsquo says Lynch lsquoWe are in the process of planning for the first field deployment in Korea on multiple bridges and it is anticipated that the sensors will be installed by the end of 2008rsquo

While reluctant to predict the future Lynch has great hopes for the technology lsquoWith major funded research programmes in multifunctional materials I am certain we will see more of these types of self-sensing materials in the future and perhaps in industrial applications within

three to five yearsrsquolsquoThese sensors work on critical

bridge components just like skin on our bodiesrsquo says civil engineering expert Victor Li lsquoThey tell you where it hurts all by themselves The potential to better manage infrastructure in relation to improved maintenance and enhanced safety is enormousrsquo

Nanoscale blasting improves magnetic sensor performance

Researchers at the National Institute of Standards

and Technology (NIST) in Gaithersburg US have demonstrated that carpeting the semiconductor layers used in hard drive sensors with tiny pits allows engineers to adjust the electrical resistance of the layers without changing any other part of the processing or design

Two recent developments in magnetic sensor technology include giant magneto-resistance (GMR) and magnetic tunnel junction (MTJ) sensors GMR sensors which have a low-resistance metal buffer layer are fast but give weak signals that are difficult to detect MTJ sensors use a high-resistance insulating buffer that leads to a strong signal but the response time is too slow for high-speed disk drives

Josh Pomeroy and his NIST colleagues have come up with a compromise solution that



nanomaterials news

Multi-height silicon oxide nanostructure created using CAD directed and automated AFM-based local anodic oxidation



Multifunction carbon nanotube composite sensing skin for structure

Source University of Michigan


involves using highly-charged ions (HCI) to blast little craters in an MTJ buffer These pits can then act like tiny GMR sensors leaving the rest to behave as an MTJ sensor

Implementing the process outside of the lab is a question of economics rather than technology says Pomeroy lsquoThe

technical part is commercially available through a handful of companies HCI sources could likely be implemented into a standard sputter deposition system relatively easily for one with adequate resourcesrsquo

lsquoHighly charged ions have great potential as a new (gentle) tool for inducing surface modifications

and surface nanostructuresrsquo says Friedrich Aumayr an HCI expert at the Technical University of Vienna Austria who has been following the NIST work with much interest

The NIST researchers are now working to incorporate their modified layers into working magnetic sensors Here they have to consider not only device resistance but also tunnel magneto-resistance sensitivity temperature dependence and bias (voltage) dependence lsquoWe have been quite pleased with our preliminary results and are working to improve our processing in order to present a clear and convincing resultrsquo says Pomeroy

There is a provisional patent on the technique and NIST is open to licensing agreements andor collaborative development

Friends of the Earth urges consumers to avoid nanotech sunscreens

The US branch of the environmentalist

organisation Friends of the Earth (FoE) has published a consumer

guide to nanotech sunscreens As well as encouraging shoppers to avoid such products FoE is demanding strict labelling and regulation of nanomaterials in consumer products

Based on a survey of 120 manufacturers the guide ranks sunscreen brands with a colour-coded scale ranging from green

(nano-free) to yellow (may contain engineered nanoparticles) to red (contains nanoparticles)

FoErsquos report discusses the potential dangers of nanoscale forms of sun-blocking chemicals such as zinc oxide and titanium dioxide A number of toxicological and other scientific studies are cited but there is no mention of conflicting studies of the same materials or caveats that scientists have attached to their research results

Some of the points raised in the report echo detailed recommendations made by various nanotechnology risk experts but FoE goes further and demands that government places an immediate moratorium on the commercial release of engineered nanomaterials until they have been proven safe There is reference in the report to the precautionary principle but no explanation as to how this could be implemented in practice

The guidersquos author Ian Illuminato says that while nanotechnology may lsquoprovide useful tools for environmental stewardshiprsquo it is currently overshadowed by irresponsible commercial development and lacks proper human and environmental health and safety considerations

lsquoFor nanotechnology to become truly useful to society and the environment we first need to take a step back and look at current pro-active solutions we have to the many issues nanotechnology promises to resolversquo says Illuminato



nanomaterials news

Illustration of a technique for selectively modifying the electrical resistance of a semiconductor device layer Highly charged xenon ions strike the nanometre-thick buffer layer digging tiny pits into its surface and the result is likened to lsquoa yard dug up by demented terrierrsquo The nanoscale pits reduce the electrical resistance of the layers and may function as nanoscale giant magneto-resistance sensors embedded in a magnetic tunnel junction sensor

Source NIST


Richard Denison senior scientist

Environmental Defense

05

Industry profile

EPA ndash too little too late on nanomaterial risks



The US Environmental Protection Agencyrsquos

Nanoscale Materials

Stewardship Program has recently come under fire from scientific and policy experts for its inconsistency and lack of regulatory teeth Now joining the chorus of critics is Environmental Defense a science and economics- centred advocacy group founded in the late 1960s as part of a campaign against the pesticide DDT

Environmental Defense was represented on the government advisory committee that two years ago urged the EPA to launch a nanomaterials stewardship programme The organisationrsquos senior scientist Richard Denison recently testified at an EPA-hosted public meeting on the proposals lsquoTwo years in the making EPArsquos tepid proposals have actually set back the clockrsquo said Denison lsquoAs a government response to addressing the possible downsides of the nanotechnology revolution itrsquos simply too little too latersquo

It should be noted that the EPA plans follow the UK governmentrsquos launch last year of a voluntary reporting

two years ago ndash worse than stasis I agree the EU is doing no better

Q Do you see voluntary reporting programmes as inherently worthless A Voluntary programmes only work if there is a meaningful regulatory backstop and the will to use it Even then critical elements must be included like specific timelines for signing up providing data etc We submitted comments to the UK government along these lines when it sought comment on its proposal but the needed specifics werenrsquot included The results speak for themselves Policymakers seem to act like lsquobeggars canrsquot be choosersrsquo when designing these voluntary programmes When participation lags they then want to offer incentives that undermine the original purpose such as overly broad protection for confidential business information allowance for self-selective reporting etc

Q Is the EPA acting as a coherent body on nanotechnology A The way EPA sees it (in my view of course) their decision as to what nanomaterials will

QampA

be lsquonewrsquo clarifies those materials that will be subject to the EPArsquos pre-market review (with all its weaknesses but at least itrsquos something) The voluntary programme is intended to try to do something to deal with the remainder the lsquoexistingrsquo nanomaterials Under the Toxic Substances Control Act EPArsquos authorities to require testing of existing substances or to actually regulate them are extremely limited so they turn instead to voluntary approaches

The EPA was invited to comment on Environmental Defensersquos critique of the nanomaterials stewardship proposals

programme Just seven companies have so far signed up to the British scheme along with two academic research bodies Environmental Defense sees the same thing happening in the US unless the EPA is far more aggressive in protecting the public and environment from potential risks associated with engineered nanomaterials

Here we discuss with Richard Denison his organisationrsquos criticism of the EPA proposals

Q How can you say that proposals have lsquoset back the clockrsquo The US appears to be in stasis as far as nanotechnology stewardship is concerned and one could argue that the EUrsquos efforts are little betterA Two years ago the EPA solicited (from its own multi-stakeholder federal advisory committee) and accepted a much more fleshed out proposal for a voluntary programme coupled with regulatory backstops and clear timelines That proposal was extensively publicly vetted Fast-forward two years the EPA now issues a lsquoconceptrsquo paper lacking these critical elements Wersquore back to less than where we were

Engineers in the US have come up with

a solution for cooling microchips of the future With the shrinking size and increasing power of microprocessors dealing with the heat they generate is critical Heatsinks and fans are traditionally used for this purpose but engineers at Purdue

University in Indiana US have developed a device that blows a cooling breeze of charged particles over computer chips

In collaboration with US bluechip Intel Corporation Suresh Garimella and his colleagues have shown that ionic wind engines could improve microchip cooling more than two- fold when used in combination with traditional techniques

Garimellarsquos wind engines work by ionising air molecules and pulling them with an electric field Electrons emitted by a high-voltage electrode collide with neutral air molecules creating positively-charged ions that are attracted back toward the electrode creating a bulk flow or ionic wind

With a conventional fan air molecules closest to the surface remain stationary Ionic wind engines can overcome this so-called lsquono-slip effectrsquo by distorting the boundary layer increasing heat transfer from the surface

lsquoWe expect that once the research and development work are completed the added cost would be nominalrsquo says Garimella lsquoThe geometric complexity is minimal though one would have to allow for actuating the electrodes

This should not be particularly difficult to bring aboutrsquo

The focus of the ongoing research work is on reducing the size to the micro-scale so that the device can operate at a potential of around 100 volts

lsquoIt is an interesting idearsquo says Texas AampM University physicist Laszlo Kish lsquoOn the practical side the most significant problems (in order of impact) are progressive dust collection and frequent cleaning needs charging of the hardware environment and protecting the hardware against electrostatic breakdown and ozone generation as a side effectrsquo

Garimella stresses that the currents and ion concentrations involved are low so the issues raised by Kish should not be significant Also the goal is to move to field-emission devices in which case the voltages would be reduced by an order of magnitude

Mass production process for nanogap electrodes developed

Researchers at the University of

Pennsylvania have

developed a process for the parallel mass-production of nanogap electrodes for use in molecular-scale electronic devices

Physics professor Charlie

Johnson postdoc Doug

Strachan and research student Danvers Johnston developed the single-step process using a technique known as feedback controlled electromigration or FCE

None of the existing approaches for producing nanogaps have proved viable for the parallel fabrication of sub-5nm gaps as required for very large scale integrated molecular circuits FCE has been used already to create individual nanoscale junctions but this latest development is the first example of the simultaneous fabrication of multiple nanogaps

In a paper published in the journal Nano Letters the researchers describe the simultaneous balancing of 16 nanogaps constructed from arrays of thin gold leads connected by narrow constrictions less than 100nm in width Passing a current through the leads forces electrons through the constrictions causing them to narrow in response to electromigration The tendency of electrons to follow paths of least resistance ensures that the process occurs simultaneously across the constrictions

Ionic wind could cool future computers


06nanomaterials news


Two infrared images show the cooling effect of ionic wind engine The red image shows the hot surface of a mock computer chip heated to about 60˚C and the blue image demonstrates that the device was able to cool the surface to about 35˚C

Source Birck Nanotechnology Center

lsquoThe balancing occurs because the applied current gets ldquopushed awayrdquo from most-formed gaps towards the least-formed onesrsquo says Strachan The end result is gaps roughly a nanometre in width with atomic-scale uniformity

lsquoScaling-up the nanogap formation should be quite straight forwardrsquo says Strachan lsquoIndustrial-scale lithography tools should be quite capable of fabricating much larger arrays These will be susceptible to becoming hot as the feedback controlled electromigration proceeds but the arrays could be precisely engineered to minimise this deleterious heatingrsquo

Strachan adds that the next major challenge is to reproducibly snap molecules into place between the nanogaps through self-assembly lsquoThis is ongoing research but has seen significant progress in the last two years ndash so we are optimisticrsquo

Self-assembly of conductive nanowire arrays

Canadian researchers have devised a novel way of

laying out arrays of electrically-conductive nanowires on silicon chips The technique which is

compatible with existing silicon-based processes could be used to produce interconnects for the next generation of microchips

Optical diffraction limits the resolution of photolithographic techniques traditionally used for microchip fabrication For nanoscale circuits another approach must be employed and chemists Jillian Buriak Steven Chai and their colleagues at the National Institute for Nanotechnology in Edmonton chose to attack the problem with polymer self-assembly

The first step in the process described in the journal Nature Nanotechnology is to introduce polystyrene- based block copolymers into micron-scale channels on a silicon surface These block copolymers then spontaneously self-assemble into lines as narrow as 10nm across are loaded with platinum ions in water and the polymer removed by a plasma treatment leaving behind nanowires with a variety of shapes and lengths

Chai describes the work as


copyPira International 2007

ISSN 1478-7059

Published fortnightly byPira International LtdCleeve Road LeatherheadSurrey KT22 7RUT +44(0)1372 802080F +44(0)1372 802079E publicationspira-internationalcomW wwwintertechpiracom

ReporterDr Francis Sedgemore

Managing editorChantal Borciani

Editor-in-chiefSara Ver-Bruggen

PublisherPhilip Swinden

DesignerAndrew Barron

Produced byMoot Editorial and Design Services


The electrical property is just one example function we have demonstratedSteven Chai chemist National

Institute for Nanotechnologyrsquolsquo

a general way of incorporating metal ions into block copolymers and then converting to aligned conductive nanowires via self-assembly The next stage is make similar wires from copper ferromagnetic metals and other functional materials

lsquoThe electrical property is just one example function we have demonstratedrsquo says Chai lsquoWe are also going to explore other properties such as the optical and magnetic characteristics of the deposited material that can be used for functional devicesrsquo

So far the resulting material quality is largely unexplored but Brookhaven National Laboratory physicist Charles Black in his Nature News amp Views comment on the work notes that the nanowire conductivity is not yet high enough for microelectronics applications and edge roughness needs to be brought down to less than 12nm

Chai and his co-workers are currently looking into these issues but Chai agrees with Black that the material in its existing state could be used for low-cost sensor devices

nanomaterials news


Schematic of a process used to produce metallic nanowires on a silicon substrate by self-assembly of block copolymers (P2VP)

Source ldquoNanowire arrays build themselvesrdquo Charles T Black Nature Nanotech 2 464 (2007)

Researchers at Duke University in North

Carolina US have adapted an established design and manufacturing process to reproduce structures with single molecule-sized features The development could help make the industrial scale fabrication of nanoscale devices feasible while capitalising on skills possessed by todayrsquos engineering workforce

Using the computing language of macroscale milling machines to guide the tip of an atomic force microscope (AFM) the system devised by Matthew Johannes Daniel Cole and

(computer numerical control) machining to articulate the microscope

probe in two dimensions They then vary the voltage applied to the probe using information stored in the third dimension of a computer-aided design drawing and this provides control over feature height on the surface

lsquoThe technique will allow others to build ldquoprototyperdquo devices in laboratories that will enable basic research with equipment that is relatively cost effectiversquo says Lynch lsquoOur primary objective is to provide researchers with enabling tools that will accelerate the development phase of nanotechnology

lsquoThe research efforts at Duke illustrate the effectiveness of innovative ideas on ways to combine naturersquos tools for replication with the power of employing engineering tools to automate the

Automation of nanotech manufacturing with computer-aided design



Robert Clark can reproduce three-dimensional silicon oxide nanostructures through a process known as anodisation nanolithography

In this process oxides are built up on semiconductor and metal surfaces by applying an electric field in the presence of trace amounts of water An advantage of using an AFM is that the structures can be visualised as they are being made

What Clark and his colleagues have done is to implement 3-D control of the deposition process through the use of so-called lsquog-codersquo from CNC

nanomaterials news

444 Cont from page 1

power heart pacemakers and other medical devices

lsquoCellulose is very stable towards mammalian enzymes and under physiological conditionsrsquo says Linhardt

lsquoCellulose is also relatively biocompatible Other medical uses of our paper super- capacitor might be as disposable defibrillatorsrsquo

Medical applications will take some time to realise and Linhardt sees supercapacitors as

Battery made from cellulose paper with aligned carbon nanotubes

Source Victor PushparajRensselaer Polytechnic Institute

the first commercial development of the storage devices lsquoThe power storage density is comparable with current devices on the market and they are flexible and have a high range of operating temperaturesrsquo he says

The researchers have yet to develop a way of inexpensively mass-producing the paper batteries and capacitors but the goal is film casting and roll-to-roll printing They are also looking at boosting the efficiency of the devices

lsquoI think this is a novel idea with great potentialrsquo says MIT chemical engineer Robert

Langer lsquoIt could be a very important advance in the energy storage arearsquo


Three-dimensional design and replication of silicon oxide nanostructures using an atomic force microscope
























nanomaterials news


























nanomaterials news


Source NIST




05

Industry profile





Nanoscale Materials







QampA



















Pennsylvania have

























ISSN 1478-7059















nanomaterials news


























nanomaterials news


























nanomaterials news


Source NIST




05

Industry profile





Nanoscale Materials







QampA



















Pennsylvania have

























ISSN 1478-7059















nanomaterials news























nanomaterials news


Source NIST




05

Industry profile





Nanoscale Materials







QampA



















Pennsylvania have

























ISSN 1478-7059















nanomaterials news






05

Industry profile





Nanoscale Materials







QampA



















Pennsylvania have

























ISSN 1478-7059















nanomaterials news

















Pennsylvania have

























ISSN 1478-7059















nanomaterials news
















ISSN 1478-7059















nanomaterials news




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nanomaterials news - University of Kentucky · 2010. 1. 21. · (nano-free) to yellow (may contain...

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