Category Archives: nanotechnology

Ministry’s new women’s shirt: a technical marvel

It seems there’s another entry into the textile business, a women’s dress shirt made of a technical textile. A Sept. 13, 2016 article by Elizabeth Segran for Fast Company describes this ‘miracle’ piece of apparel,

There are few items of clothing professional women love more than a well-draped silk shirt. They’re the equivalent of men’s well-tailored Oxford shirts: classic, elegant, and versatile enough to look appropriate in almost any business context. But they’re also difficult to maintain: Silk wrinkles easily, doesn’t absorb perspiration, and needs to be dry cleaned.

Boston-based fashion brand Ministry (formerly Ministry of Supply) has heard our lament. …

Ministry gathered …  feedback and spent two years creating a high-performance women’s work shirt as part of its debut womenswear collection, launching today [Sept. 13, 2016]. Until now, the five-year-old company has been focused on creating menswear made with cutting-edge new textiles, but cofounder Gihan Amarasiriwardena explains that when they were developing the womenswear collection, they didn’t just remake their men’s garments in women’s sizes.

Here’s an image of the shirt in black,

[downloaded from http://ministry.co/collections/womens]

[downloaded from http://ministry.co/collections/womens]

Segran’s article mostly extolls its benefits but there is a little technical information,

Their brand-new, aptly named Easier Than Silk Shirt looks and feels like silk, but is actually made from a Japanese technical fabric (i.e., a textile engineered to perform functions, like protecting the wearer from extremely high temperatures). It drapes nicely, wicks moisture, is wrinkle-resistant, and can be thrown in a regular washer and dryer. I tested the shirt on a typical Monday. This meant getting dressed at 7 a.m., taking my baby to a health checkup—where she proceeded to drool on me—wiping myself off for a lunch interview, then heading to a coffee shop to write for several hours before going to a book launch party. By the time I got home that evening and looked in the mirror, the shirt was somehow crease-free and there were no moisture blotches in sight.

When Ministry claims to “engineer a shirt,” it does not mean this in a metaphorical sense. The by [sic] three MIT students, Amarasiriwardena, Aman Advani, and Kit Hickey; the former two were trained as engineers. Every aspect of Ministry’s design process incorporates scientific thinking, from introducing NASA temperature-regulating textile technology into dress shirts to using equipment to test each garment before it hits the market. The Ministry headquarters in Boston is full of machines, including one that pulls at fabric to see how well it is able to recover from being stretched, and computer systems that offer 3D modeling of the human form.

I wonder if Teijin (first mentioned here in a July 19, 2010 posting about their now defunct ‘morphotex’ [based on the nanostructures on a Morpho butterfly’s wing] fabric) is the Japanese company producing Ministry’s technical textile. Ministry’s company website is less focused on the technology than on the retail aspect of their business so if the technical information is there, it’s not immediately obvious.

Carbon nanotubes that can outperform silicon

According to a Sept. 2, 2016 news item on phys.org, researchers at the University of Wisconsin-Madison have produced carbon nanotube transistors that outperform state-of-the-art silicon transistors,

For decades, scientists have tried to harness the unique properties of carbon nanotubes to create high-performance electronics that are faster or consume less power—resulting in longer battery life, faster wireless communication and faster processing speeds for devices like smartphones and laptops.

But a number of challenges have impeded the development of high-performance transistors made of carbon nanotubes, tiny cylinders made of carbon just one atom thick. Consequently, their performance has lagged far behind semiconductors such as silicon and gallium arsenide used in computer chips and personal electronics.

Now, for the first time, University of Wisconsin-Madison materials engineers have created carbon nanotube transistors that outperform state-of-the-art silicon transistors.

Led by Michael Arnold and Padma Gopalan, UW-Madison professors of materials science and engineering, the team’s carbon nanotube transistors achieved current that’s 1.9 times higher than silicon transistors. …

A Sept. 2, 2016 University of Wisconsin-Madison news release (also on EurekAlert) by Adam Malecek, which originated the news item, describes the research in more detail and notes that the technology has been patented,

“This achievement has been a dream of nanotechnology for the last 20 years,” says Arnold. “Making carbon nanotube transistors that are better than silicon transistors is a big milestone. This breakthrough in carbon nanotube transistor performance is a critical advance toward exploiting carbon nanotubes in logic, high-speed communications, and other semiconductor electronics technologies.”

This advance could pave the way for carbon nanotube transistors to replace silicon transistors and continue delivering the performance gains the computer industry relies on and that consumers demand. The new transistors are particularly promising for wireless communications technologies that require a lot of current flowing across a relatively small area.

As some of the best electrical conductors ever discovered, carbon nanotubes have long been recognized as a promising material for next-generation transistors.

Carbon nanotube transistors should be able to perform five times faster or use five times less energy than silicon transistors, according to extrapolations from single nanotube measurements. The nanotube’s ultra-small dimension makes it possible to rapidly change a current signal traveling across it, which could lead to substantial gains in the bandwidth of wireless communications devices.

But researchers have struggled to isolate purely carbon nanotubes, which are crucial, because metallic nanotube impurities act like copper wires and disrupt their semiconducting properties — like a short in an electronic device.

The UW–Madison team used polymers to selectively sort out the semiconducting nanotubes, achieving a solution of ultra-high-purity semiconducting carbon nanotubes.

“We’ve identified specific conditions in which you can get rid of nearly all metallic nanotubes, where we have less than 0.01 percent metallic nanotubes,” says Arnold.

Placement and alignment of the nanotubes is also difficult to control.

To make a good transistor, the nanotubes need to be aligned in just the right order, with just the right spacing, when assembled on a wafer. In 2014, the UW–Madison researchers overcame that challenge when they announced a technique, called “floating evaporative self-assembly,” that gives them this control.

The nanotubes must make good electrical contacts with the metal electrodes of the transistor. Because the polymer the UW–Madison researchers use to isolate the semiconducting nanotubes also acts like an insulating layer between the nanotubes and the electrodes, the team “baked” the nanotube arrays in a vacuum oven to remove the insulating layer. The result: excellent electrical contacts to the nanotubes.

The researchers also developed a treatment that removes residues from the nanotubes after they’re processed in solution.

“In our research, we’ve shown that we can simultaneously overcome all of these challenges of working with nanotubes, and that has allowed us to create these groundbreaking carbon nanotube transistors that surpass silicon and gallium arsenide transistors,” says Arnold.

The researchers benchmarked their carbon nanotube transistor against a silicon transistor of the same size, geometry and leakage current in order to make an apples-to-apples comparison.

They are continuing to work on adapting their device to match the geometry used in silicon transistors, which get smaller with each new generation. Work is also underway to develop high-performance radio frequency amplifiers that may be able to boost a cellphone signal. While the researchers have already scaled their alignment and deposition process to 1 inch by 1 inch wafers, they’re working on scaling the process up for commercial production.

Arnold says it’s exciting to finally reach the point where researchers can exploit the nanotubes to attain performance gains in actual technologies.

“There has been a lot of hype about carbon nanotubes that hasn’t been realized, and that has kind of soured many people’s outlook,” says Arnold. “But we think the hype is deserved. It has just taken decades of work for the materials science to catch up and allow us to effectively harness these materials.”

The researchers have patented their technology through the Wisconsin Alumni Research Foundation.

Interestingly, at least some of the research was publicly funded according to the news release,

Funding from the National Science Foundation, the Army Research Office and the Air Force supported their work.

Will the public ever benefit financially from this research?

Innovation and two Canadian universities

I have two news bits and both concern the Canadian universities, the University of British Columbia (UBC) and the University of Toronto (UofT).

Creative Destruction Lab – West

First, the Creative Destruction Lab, a technology commercialization effort based at UofT’s Rotman School of Management, is opening an office in the west according to a Sept. 28, 2016 UBC media release (received via email; Note: Links have been removed; this is a long media release which interestingly does not mention Joseph Schumpeter the man who developed the economic theory which he called: creative destruction),

The UBC Sauder School of Business is launching the Western Canadian version of the Creative Destruction Lab, a successful seed-stage program based at UofT’s Rotman School of Management, to help high-technology ventures driven by university research maximize their commercial impact and benefit to society.

“Creative Destruction Lab – West will provide a much-needed support system to ensure innovations formulated on British Columbia campuses can access the funding they need to scale up and grow in-province,” said Robert Helsley, Dean of the UBC Sauder School of Business. “The success our partners at Rotman have had in helping commercialize the scientific breakthroughs of Canadian talent is remarkable and is exactly what we plan to replicate at UBC Sauder.”

Between 2012 and 2016, companies from CDL’s first four years generated over $800 million in equity value. It has supported a long line of emerging startups, including computer-human interface company Thalmic Labs, which announced nearly USD $120 million in funding on September 19, one of the largest Series B financings in Canadian history.

Focusing on massively scalable high-tech startups, CDL-West will provide coaching from world-leading entrepreneurs, support from dedicated business and science faculty, and access to venture capital. While some of the ventures will originate at UBC, CDL-West will also serve the entire province and extended western region by welcoming ventures from other universities. The program will closely align with existing entrepreneurship programs across UBC, including, e@UBC and HATCH, and actively work with the BC Tech Association [also known as the BC Technology Industry Association] and other partners to offer a critical next step in the venture creation process.

“We created a model for tech venture creation that keeps startups focused on their essential business challenges and dedicated to solving them with world-class support,” said CDL Founder Ajay Agrawal, a professor at the Rotman School of Management and UBC PhD alumnus.

“By partnering with UBC Sauder, we will magnify the impact of CDL by drawing in ventures from one of the country’s other leading research universities and B.C.’s burgeoning startup scene to further build the country’s tech sector and the opportunities for job creation it provides,” said CDL Director, Rachel Harris.

CDL uses a goal-setting model to push ventures along a path toward success. Over nine months, a collective of leading entrepreneurs with experience building and scaling technology companies – called the G7 – sets targets for ventures to hit every eight weeks, with the goal of maximizing their equity-value. Along the way ventures turn to business and technology experts for strategic guidance on how to reach goals, and draw on dedicated UBC Sauder students who apply state-of the-art business skills to help companies decide which market to enter first and how.

Ventures that fail to achieve milestones – approximately 50 per cent in past cohorts – are cut from the process. Those that reach their objectives and graduate from the program attract investment from the G7, as well as other leading venture-capital firms.

Currently being assembled, the CDL-West G7 will be comprised of entrepreneurial luminaries, including Jeff Mallett, the founding President, COO and Director of Yahoo! Inc. from 1995-2002 – a company he led to $4 billion in revenues and grew from a startup to a publicly traded company whose value reached $135 billion. He is now Managing Director of Iconica Partners and Managing Partner of Mallett Sports & Entertainment, with ventures including the San Francisco Giants, AT&T Park and Mission Rock Development, Comcast Bay Area Sports Network, the San Jose Giants, Major League Soccer, Vancouver Whitecaps FC, and a variety of other sports and online ventures.

Already bearing fruit, the Creative Destruction Lab partnership will see several UBC ventures accepted into a Machine Learning Specialist Track run by Rotman’s CDL this fall. This track is designed to create a support network for enterprises focused on artificial intelligence, a research strength at UofT and Canada more generally, which has traditionally migrated to the United States for funding and commercialization. In its second year, CDL-West will launch its own specialist track in an area of strength at UBC that will draw eastern ventures west.

“This new partnership creates the kind of high impact innovation network the Government of Canada wants to encourage,” said Brandon Lee, Canada’s Consul General in San Francisco, who works to connect Canadian innovation to customers and growth capital opportunities in Silicon Valley. “By collaborating across our universities to enhance our capacity to turn the scientific discoveries into businesses in Canada, we can further advance our nation’s global competitiveness in the knowledge-based industries.”

The Creative Destruction Lab is guided by an Advisory Board, co-chaired by Vancouver-based Haig Farris, a pioneer of the Canadian venture capitalist industry, and Bill Graham, Chancellor of Trinity College at UofT and former Canadian cabinet minister.

“By partnering with Rotman, UBC Sauder will be able to scale up its support for high-tech ventures extremely quickly and with tremendous impact,” said Paul Cubbon, Leader of CDL-West and a faculty member at UBC Sauder. “CDL-West will act as a turbo booster for ventures with great ideas, but which lack the strategic roadmap and funding to make them a reality.”

CDL-West launched its competitive application process for the first round of ventures that will begin in January 2017. Interested ventures are encouraged to submit applications via the CDL website at: www.creativedestructionlab.com

Background

UBC Technology ventures represented at media availability

Awake Labs is a wearable technology startup whose products measure and track anxiety in people with Autism Spectrum Disorder to better understand behaviour. Their first device, Reveal, monitors a wearer’s heart-rate, body temperature and sweat levels using high-tech sensors to provide insight into care and promote long term independence.

Acuva Technologies is a Vancouver-based clean technology venture focused on commercializing breakthrough UltraViolet Light Emitting Diode technology for water purification systems. Initially focused on point of use systems for boats, RVs and off grid homes in North American market, where they already have early sales, the company’s goal is to enable water purification in households in developing countries by 2018 and deploy large scale systems by 2021.

Other members of the CDL-West G7 include:

Boris Wertz: One of the top tech early-stage investors in North America and the founding partner of Version One, Wertz is also a board partner with Andreessen Horowitz. Before becoming an investor, Wertz was the Chief Operating Officer of AbeBooks.com, which sold to Amazon in 2008. He was responsible for marketing, business development, product, customer service and international operations. His deep operational experience helps him guide other entrepreneurs to start, build and scale companies.

Lisa Shields: Founder of Hyperwallet Systems Inc., Shields guided Hyperwallet from a technology startup to the leading international payments processor for business to consumer mass payouts. Prior to founding Hyperwallet, Lisa managed payments acceptance and risk management technology teams for high-volume online merchants. She was the founding director of the Wireless Innovation Society of British Columbia and is driven by the social and economic imperatives that shape global payment technologies.

Jeff Booth: Co-founder, President and CEO of Build Direct, a rapidly growing online supplier of home improvement products. Through custom and proprietary web analytics and forecasting tools, BuildDirect is reinventing and redefining how consumers can receive the best prices. BuildDirect has 12 warehouse locations across North America and is headquartered in Vancouver, BC. In 2015, Booth was awarded the BC Technology ‘Person of the Year’ Award by the BC Technology Industry Association.

Education:

CDL-west will provide a transformational experience for MBA and senior undergraduate students at UBC Sauder who will act as venture advisors. Replacing traditional classes, students learn by doing during the process of rapid equity-value creation.

Supporting venture development at UBC:

CDL-west will work closely with venture creation programs across UBC to complete the continuum of support aimed at maximizing venture value and investment. It will draw in ventures that are being or have been supported and developed in programs that span campus, including:

University Industry Liaison Office which works to enable research and innovation partnerships with industry, entrepreneurs, government and non-profit organizations.

e@UBC which provides a combination of mentorship, education, venture creation, and seed funding to support UBC students, alumni, faculty and staff.

HATCH, a UBC technology incubator which leverages the expertise of the UBC Sauder School of Business and entrepreneurship@UBC and a seasoned team of domain-specific experts to provide real-world, hands-on guidance in moving from innovative concept to successful venture.

Coast Capital Savings Innovation Hub, a program base at the UBC Sauder Centre for Social Innovation & Impact Investing focused on developing ventures with the goal of creating positive social and environmental impact.

About the Creative Destruction Lab in Toronto:

The Creative Destruction Lab leverages the Rotman School’s leading faculty and industry network as well as its location in the heart of Canada’s business capital to accelerate massively scalable, technology-based ventures that have the potential to transform our social, industrial, and economic landscape. The Lab has had a material impact on many nascent startups, including Deep Genomics, Greenlid, Atomwise, Bridgit, Kepler Communications, Nymi, NVBots, OTI Lumionics, PUSH, Thalmic Labs, Vertical.ai, Revlo, Validere, Growsumo, and VoteCompass, among others. For more information, visit www.creativedestructionlab.com

About the UBC Sauder School of Business

The UBC Sauder School of Business is committed to developing transformational and responsible business leaders for British Columbia and the world. Located in Vancouver, Canada’s gateway to the Pacific Rim, the school is distinguished for its long history of partnership and engagement in Asia, the excellence of its graduates, and the impact of its research which ranks in the top 20 globally. For more information, visit www.sauder.ubc.ca

About the Rotman School of Management

The Rotman School of Management is located in the heart of Canada’s commercial and cultural capital and is part of the University of Toronto, one of the world’s top 20 research universities. The Rotman School fosters a new way to think that enables graduates to tackle today’s global business and societal challenges. For more information, visit www.rotman.utoronto.ca.

It’s good to see a couple of successful (according to the news release) local entrepreneurs on the board although I’m somewhat puzzled by Mallett’s presence since, if memory serves, Yahoo! was not doing that well when he left in 2002. The company was an early success but utterly dwarfed by Google at some point in the early 2000s and these days, its stock (both financial and social) has continued to drift downwards. As for Mallett’s current successes, there is no mention of them.

Reuters Top 100 of the world’s most innovative universities

After reading or skimming through the CDL-West news you might think that the University of Toronto ranked higher than UBC on the Reuters list of the world’s most innovative universities. Before breaking the news about the Canadian rankings, here’s more about the list from a Sept, 28, 2016 Reuters news release (receive via email),

Stanford University, the Massachusetts Institute of Technology and Harvard University top the second annual Reuters Top 100 ranking of the world’s most innovative universities. The Reuters Top 100 ranking aims to identify the institutions doing the most to advance science, invent new technologies and help drive the global economy. Unlike other rankings that often rely entirely or in part on subjective surveys, the ranking uses proprietary data and analysis tools from the Intellectual Property & Science division of Thomson Reuters to examine a series of patent and research-related metrics, and get to the essence of what it means to be truly innovative.

In the fast-changing world of science and technology, if you’re not innovating, you’re falling behind. That’s one of the key findings of this year’s Reuters 100. The 2016 results show that big breakthroughs – even just one highly influential paper or patent – can drive a university way up the list, but when that discovery fades into the past, so does its ranking. Consistency is key, with truly innovative institutions putting out groundbreaking work year after year.

Stanford held fast to its first place ranking by consistently producing new patents and papers that influence researchers elsewhere in academia and in private industry. Researchers at the Massachusetts Institute of Technology (ranked #2) were behind some of the most important innovations of the past century, including the development of digital computers and the completion of the Human Genome Project. Harvard University (ranked #3), is the oldest institution of higher education in the United States, and has produced 47 Nobel laureates over the course of its 380-year history.

Some universities saw significant movement up the list, including, most notably, the University of Chicago, which jumped from #71 last year to #47 in 2016. Other list-climbers include the Netherlands’ Delft University of Technology (#73 to #44) and South Korea’s Sungkyunkwan University (#66 to #46).

The United States continues to dominate the list, with 46 universities in the top 100; Japan is once again the second best performing country, with nine universities. France and South Korea are tied in third, each with eight. Germany has seven ranked universities; the United Kingdom has five; Switzerland, Belgium and Israel have three; Denmark, China and Canada have two; and the Netherlands and Singapore each have one.

You can find the rankings here (scroll down about 75% of the way) and for the impatient, the University of British Columbia ranked 50th and the University of Toronto 57th.

The biggest surprise for me was that China, like Canada, had two universities on the list. I imagine that will change as China continues its quest for science and innovation dominance. Given how they tout their innovation prowess, I had one other surprise, the University of Waterloo’s absence.

Graphene in the bone

An international team of US, Brazilian, and Indian scientists has developed a graphene-based material they believe could be used in bone implants. From a Sept. 2, 2016 news item on ScienceDaily,

Flakes of graphene welded together into solid materials may be suitable for bone implants, according to a study led by Rice University scientists.

The Rice lab of materials scientist Pulickel Ajayan and colleagues in Texas, Brazil and India used spark plasma sintering to weld flakes of graphene oxide into porous solids that compare favorably with the mechanical properties and biocompatibility of titanium, a standard bone-replacement material.

A Sept. 2, 2016 Rice University news release (also on EurekAlert), which originated the news item, explains the work in more detail,

The researchers believe their technique will give them the ability to create highly complex shapes out of graphene in minutes using graphite molds, which they believe would be easier to process than specialty metals.

“We started thinking about this for bone implants because graphene is one of the most intriguing materials with many possibilities and it’s generally biocompatible,” said Rice postdoctoral research associate Chandra Sekhar Tiwary, co-lead author of the paper with Dibyendu Chakravarty of the International Advanced Research Center for Powder Metallurgy and New Materials in Hyderabad, India. “Four things are important: its mechanical properties, density, porosity and biocompatibility.”

Tiwary said spark plasma sintering is being used in industry to make complex parts, generally with ceramics. “The technique uses a high pulse current that welds the flakes together instantly. You only need high voltage, not high pressure or temperatures,” he said. The material they made is nearly 50 percent porous, with a density half that of graphite and a quarter of titanium metal. But it has enough compressive strength — 40 megapascals — to qualify it for bone implants, he said. The strength of the bonds between sheets keeps it from disintegrating in water.

The researchers controlled the density of the material by altering the voltage that delivers the highly localized blast of heat that makes the nanoscale welds. Though the experiments were carried out at room temperature, the researchers made graphene solids of various density by raising these sintering temperatures from 200 to 400 degrees Celsius. Samples made at local temperatures of 300 C proved best, Tiwary said. “The nice thing about two-dimensional materials is that they give you a lot of surface area to connect. With graphene, you just need to overcome a small activation barrier to make very strong welds,” he said.

With the help of colleagues at Hysitron in Minnesota, the researchers measured the load-bearing capacity of thin sheets of two- to five-layer bonded graphene by repeatedly stressing them with a picoindenter attached to a scanning electron microscope and found they were stable up to 70 micronewtons. Colleagues at the University of Texas MD Anderson Cancer Center successfully cultured cells on the material to show its biocompatibility. As a bonus, the researchers also discovered the sintering process has the ability to reduce graphene oxide flakes to pure bilayer graphene, which makes them stronger and more stable than graphene monolayers or graphene oxide.

“This example demonstrates the possible use of unconventional materials in conventional technologies,” Ajayan said. “But these transitions can only be made if materials such as 2-D graphene layers can be scalably made into 3-D solids with appropriate density and strength.

“Engineering junctions and strong interfaces between nanoscale building blocks is the biggest challenge in achieving such goals, but in this case, spark plasma sintering seems to be effective in joining graphene sheets to produce strong 3-D solids,” he said.

The researchers have produced an animation depicting of graphene oxide layers being stacked,

A molecular dynamics simulation shows how graphene oxide layers stack when welded by spark plasma sintering. The presence of oxygen molecules at left prevents the graphene layers from bonding, as they do without oxygen at right. Courtesy of the Ajayan and Galvão groups

Here’s a link to and a citation for the paper,

3D Porous Graphene by Low-Temperature Plasma Welding for Bone Implants by Dibyendu Chakravarty, Chandra Sekhar Tiwary, Cristano F. Woellner, Sruthi Radhakrishnan4, Soumya Vinod, Sehmus Ozden, Pedro Alves da Silva Autreto, Sanjit Bhowmick, Syed Asif, Sendurai A Mani, Douglas S. Galvao, and Pulickel M. Ajayan. Advanced Materials DOI: 10.1002/adma.201603146 Version of Record online: 26 AUG 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Cooling the skin with plastic clothing

Rather that cooling or heating an entire room, why not cool or heat the person? Engineers at Stanford University (California, US) have developed a material that helps with half of that premise: cooling. From a Sept. 1, 2016 news item on ScienceDaily,

Stanford engineers have developed a low-cost, plastic-based textile that, if woven into clothing, could cool your body far more efficiently than is possible with the natural or synthetic fabrics in clothes we wear today.

Describing their work in Science, the researchers suggest that this new family of fabrics could become the basis for garments that keep people cool in hot climates without air conditioning.

“If you can cool the person rather than the building where they work or live, that will save energy,” said Yi Cui, an associate professor of materials science and engineering and of photon science at Stanford.

A Sept. 1, 2016 Stanford University news release (also on EurekAlert) by Tom Abate, which originated the news item, further explains the information in the video,

This new material works by allowing the body to discharge heat in two ways that would make the wearer feel nearly 4 degrees Fahrenheit cooler than if they wore cotton clothing.

The material cools by letting perspiration evaporate through the material, something ordinary fabrics already do. But the Stanford material provides a second, revolutionary cooling mechanism: allowing heat that the body emits as infrared radiation to pass through the plastic textile.

All objects, including our bodies, throw off heat in the form of infrared radiation, an invisible and benign wavelength of light. Blankets warm us by trapping infrared heat emissions close to the body. This thermal radiation escaping from our bodies is what makes us visible in the dark through night-vision goggles.

“Forty to 60 percent of our body heat is dissipated as infrared radiation when we are sitting in an office,” said Shanhui Fan, a professor of electrical engineering who specializes in photonics, which is the study of visible and invisible light. “But until now there has been little or no research on designing the thermal radiation characteristics of textiles.”

Super-powered kitchen wrap

To develop their cooling textile, the Stanford researchers blended nanotechnology, photonics and chemistry to give polyethylene – the clear, clingy plastic we use as kitchen wrap – a number of characteristics desirable in clothing material: It allows thermal radiation, air and water vapor to pass right through, and it is opaque to visible light.

The easiest attribute was allowing infrared radiation to pass through the material, because this is a characteristic of ordinary polyethylene food wrap. Of course, kitchen plastic is impervious to water and is see-through as well, rendering it useless as clothing.

The Stanford researchers tackled these deficiencies one at a time.

First, they found a variant of polyethylene commonly used in battery making that has a specific nanostructure that is opaque to visible light yet is transparent to infrared radiation, which could let body heat escape. This provided a base material that was opaque to visible light for the sake of modesty but thermally transparent for purposes of energy efficiency.

They then modified the industrial polyethylene by treating it with benign chemicals to enable water vapor molecules to evaporate through nanopores in the plastic, said postdoctoral scholar and team member Po-Chun Hsu, allowing the plastic to breathe like a natural fiber.

Making clothes

That success gave the researchers a single-sheet material that met their three basic criteria for a cooling fabric. To make this thin material more fabric-like, they created a three-ply version: two sheets of treated polyethylene separated by a cotton mesh for strength and thickness.

To test the cooling potential of their three-ply construct versus a cotton fabric of comparable thickness, they placed a small swatch of each material on a surface that was as warm as bare skin and measured how much heat each material trapped.

“Wearing anything traps some heat and makes the skin warmer,” Fan said. “If dissipating thermal radiation were our only concern, then it would be best to wear nothing.”

The comparison showed that the cotton fabric made the skin surface 3.6 F warmer than their cooling textile. The researchers said this difference means that a person dressed in their new material might feel less inclined to turn on a fan or air conditioner.

The researchers are continuing their work on several fronts, including adding more colors, textures and cloth-like characteristics to their material. Adapting a material already mass produced for the battery industry could make it easier to create products.

“If you want to make a textile, you have to be able to make huge volumes inexpensively,” Cui said.

Fan believes that this research opens up new avenues of inquiry to cool or heat things, passively, without the use of outside energy, by tuning materials to dissipate or trap infrared radiation.

“In hindsight, some of what we’ve done looks very simple, but it’s because few have really been looking at engineering the radiation characteristics of textiles,” he said.

Dexter Johnson (Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers] website) has written a Sept. 2, 2016 posting where he provides more technical detail about this work,

The nanoPE [nanoporous polyethylene] material is able to achieve this release of the IR heat because of the size of the interconnected pores. The pores can range in size from 50 to 1000 nanometers. They’re therefore comparable in size to wavelengths of visible light, which allows the material to scatter that light. However, because the pores are much smaller than the wavelength of infrared light, the nanoPE is transparent to the IR.

It is this combination of blocking visible light and allowing IR to pass through that distinguishes the nanoPE material from regular polyethylene, which allows similar amounts of IR to pass through, but can only block 20 percent of the visible light compared to nanoPE’s 99 percent opacity.

The Stanford researchers were also able to improve on the water wicking capability of the nanoPE material by using a microneedle punching technique and coating the material with a water-repelling agent. The result is that perspiration can evaporate through the material unlike with regular polyethylene.

For those who wish to further pursue their interest, Dexter has a lively writing style and he provides more detail and insight in his posting.

Here’s a link to and a citation for the paper,

Radiative human body cooling by nanoporous polyethylene textile by Po-Chun Hsu, Alex Y. Song, Peter B. Catrysse, Chong Liu, Yucan Peng, Jin Xie, Shanhui Fan, Yi Cui. Science  02 Sep 2016: Vol. 353, Issue 6303, pp. 1019-1023 DOI: 10.1126/science.aaf5471

This paper is open access.

Treating graphene with lasers for paper-based electronics

Engineers at Iowa State University have found a way they hope will make it easier to commercialize graphene. A Sept. 1, 2016 news item on phys.org describes the research,

The researchers in Jonathan Claussen’s lab at Iowa State University (who like to call themselves nanoengineers) have been looking for ways to use graphene and its amazing properties in their sensors and other technologies.

Graphene is a wonder material: The carbon honeycomb is just an atom thick. It’s great at conducting electricity and heat; it’s strong and stable. But researchers have struggled to move beyond tiny lab samples for studying its material properties to larger pieces for real-world applications.

Recent projects that used inkjet printers to print multi-layer graphene circuits and electrodes had the engineers thinking about using it for flexible, wearable and low-cost electronics. For example, “Could we make graphene at scales large enough for glucose sensors?” asked Suprem Das, an Iowa State postdoctoral research associate in mechanical engineering and an associate of the U.S. Department of Energy’s Ames Laboratory.

But there were problems with the existing technology. Once printed, the graphene had to be treated to improve electrical conductivity and device performance. That usually meant high temperatures or chemicals – both could degrade flexible or disposable printing surfaces such as plastic films or even paper.

Das and Claussen came up with the idea of using lasers to treat the graphene. Claussen, an Iowa State assistant professor of mechanical engineering and an Ames Laboratory associate, worked with Gary Cheng, an associate professor at Purdue University’s School of Industrial Engineering, to develop and test the idea.

A Sept. 1, 2016 Iowa State University news release (also on EurekAlert), which originated the news item, provides more detail about the intellectual property, as well as, the technology,

… They found treating inkjet-printed, multi-layer graphene electric circuits and electrodes with a pulsed-laser process improves electrical conductivity without damaging paper, polymers or other fragile printing surfaces.

“This creates a way to commercialize and scale-up the manufacturing of graphene,” Claussen said.

Two major grants are supporting the project and related research: a three-year grant from the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 11901762 and a three-year grant from the Roy J. Carver Charitable Trust. Iowa State’s College of Engineering and department of mechanical engineering are also supporting the research.

The Iowa State Research Foundation Inc. has filed for a patent on the technology.

“The breakthrough of this project is transforming the inkjet-printed graphene into a conductive material capable of being used in new applications,” Claussen said.

Those applications could include sensors with biological applications, energy storage systems, electrical conducting components and even paper-based electronics.

To make all that possible, the engineers developed computer-controlled laser technology that selectively irradiates inkjet-printed graphene oxide. The treatment removes ink binders and reduces graphene oxide to graphene – physically stitching together millions of tiny graphene flakes. The process makes electrical conductivity more than a thousand times better.

“The laser works with a rapid pulse of high-energy photons that do not destroy the graphene or the substrate,” Das said. “They heat locally. They bombard locally. They process locally.”

That localized, laser processing also changes the shape and structure of the printed graphene from a flat surface to one with raised, 3-D nanostructures. The engineers say the 3-D structures are like tiny petals rising from the surface. The rough and ridged structure increases the electrochemical reactivity of the graphene, making it useful for chemical and biological sensors.

All of that, according to Claussen’s team of nanoengineers, could move graphene to commercial applications.

“This work paves the way for not only paper-based electronics with graphene circuits,” the researchers wrote in their paper, “it enables the creation of low-cost and disposable graphene-based electrochemical electrodes for myriad applications including sensors, biosensors, fuel cells and (medical) devices.”

Here’s a link to and a citation for the paper,

3D nanostructured inkjet printed graphene via UV-pulsed laser irradiation enables paper-based electronics and electrochemical devices by Suprem R. Das, Qiong Nian, Allison A. Cargill, John A. Hondred, Shaowei Ding, Mojib Saei, Gary J. Cheng, and   Jonathan C. Claussen. Nanoscale, 2016,8, 15870-15879 DOI: 10.1039/C6NR04310K First published online 12 Jul 2016

This paper is open access but you do need to have registered for your free account to access the material.

Next generation of power lines could be carbon nanotube-coated

This research was done at the Masdar Institute in Abu Dhabi of the United Arab Emirates. From a Sept. 1, 2016 news item on Nanowerk,

A Masdar Institute Assistant Professor may have brought engineers one step closer to developing the type of next-generation power lines needed to achieve sustainable and resilient electrical power grids.

Dr. Kumar Shanmugam, Assistant Professor of Materials and Mechanical Engineering, helped develop a novel coating made from carbon nanotubes that, when layered around an aluminum-conductor composite core (ACCC) transmission line, reduces the line’s operating temperature and significantly improves its overall transmission efficiency.

An Aug. 29, 2016 Masdar Institute news release by Erica Solomon, which originated the news item, provides more detail,

The coating is made from carbon nanostructures (CNS) – which are bundles of aligned carbon nanotubes that have exceptional mechanical and electrical properties – provided by the project’s sponsor, Lockheed Martin. The second component of the coating is an epoxy resin, which is the thick material used to protect things like appliances and electronics from damage.  Together, the CNS and epoxy resin help prevent power lines from overheating, increases their current carrying capacity (the amount of current that can flow through a transmission line), while also protecting them from damages associated with lightning strikes, ice and other environmental impacts.

The researchers found that by replacing traditional steel-core transmission lines with ACCC cables layered with a CNS-epoxy coating (referred to in the study as ACCC-CNS lines), the amount of aluminum used in an ACCC cable can be reduced by 25%, making the cable significantly lighter and cheaper to produce. The span length of a transmission line can also increase by 30%, which will make it easier to transmit electricity across longer distances while the amount of current the line can carry can increase by 40%.

“The coating helps to dissipate the heat generated in the conductor more efficiently through radiation and convection, thereby preventing the cable from overheating and enabling it to carry more current farther distances,” Dr. Kumar explained.

Ultimately, the purpose of the coating is to effectively eliminate the transmission line losses. Each year, anywhere from 5% to over 10% of the overall power generated in a power plant is lost in transmission and distribution lines. Most of this electrical energy is lost in the form of heat; as current runs through a conductor (the transmission line), the conductor heats up because it resists the flow of electrons to some extent – a phenomenon known as resistive Joule heating. Resistive Joule heating causes the energy that was moving the electrons forward to change into heat energy, which means some of the generated power gets converted into heat and lost to the surrounding environment instead of getting to its intended destination (like our homes and offices).

In addition to wasting energy, resistive Joule heating can lead to overheating, which can trigger a transmission line to “sag”, or physically droop low to the ground. Sagging power lines in turn can have catastrophic effects, including short circuits and power outages.

Efforts to reduce the problem of resistive heating and energy loss in power lines have led to significant improvements in transmission line technologies. For example, in 2002 ACCC transmission cables – which feature a carbon and glass-fiber reinforced composite core wrapped in aluminum conductor wires – were invented. The ACCC conductors are lighter and more heat-resistant than traditional steel-core cables, which means they can carry more current without overheating or sagging. Today, it is estimated that over 200 power and distribution networks use ACCC transmission cables.

While the advent of composite core cables marks the first major turning point in the development of energy-efficient transmission lines, Dr. Kumar’s CNS-epoxy coating may be the second significant advancement in the evolution of sustainable power lines.

The CNS-epoxy coating works by keeping the cable’s operating temperatures low. It does this by dissipating, any generated heat away from the conductor efficiently, thereby preventing further increase in temperature of the line and avoiding the trickle-effect that often leads to overheating.

The coating is layered twice in the ACCC cable – an outer layer, which dissipates the heat and protects the cable from environmental factors like lightning strikes and foreign object impact; and an inner layer, which protects the composite core from damage caused by stray radio frequency radiation generated by the electromagnetic pulse emanating from high electric current carrying aluminum conductor

The research team utilized a multi-physics modeling framework to analyze how the CNS-epoxy coating would influence the performance of ACCC transmission line. After fabricating the coating, they characterized it, which is a critical step to determine its mechanical, thermal and electrical properties. These properties were then used in the computational and theoretical models to evaluate and predict the coating’s performance. Finally, a design tool was developed and used to find the optimal combination of parameters (core diameter, span distance and sag) needed to reduce the cable’s weight, sag, and operating temperature while increasing its span distance and current carrying capacity.

Dr. Kumar’s innovative transmission line technology research comes at a pivotal time, when countries all over the world, including the UAE, are seeking ways to reduce their carbon footprint in a concerted effort to mitigate global climate change. Turning to energy-efficient power lines that waste less power and in turn produce less carbon dioxide emissions will be an obvious choice for nations devoted to greater sustainability.

Here’s a link to and a citation for the paper,

High-Ampacity Overhead Power Lines With Carbon Nanostructure–Epoxy Composites by V. S. N. Ranjith Kumar, S. Kumar, G. Pal, and Tushar Shah. J. Eng. Mater. Technol 138(4), 041018 (Aug 09, 2016) (9 pages) Paper No: MATS-15-1217; doi: 10.1115/1.4034095

This paper is behind a paywall.

Graphene Canada and its second annual conference

An Aug. 31, 2016 news item on Nanotechnology Now announces Canada’s second graphene-themed conference,

The 2nd edition of Graphene & 2D Materials Canada 2016 International Conference & Exhibition (www.graphenecanadaconf.com) will take place in Montreal (Canada): 18-20 October, 2016.

– An industrial forum with focus on Graphene Commercialization (Abalonyx, Alcereco Inc, AMO GmbH, Avanzare, AzTrong Inc, Bosch GmbH, China Innovation Alliance of the Graphene Industry (CGIA), Durham University & Applied Graphene Materials, Fujitsu Laboratories Ltd., Hanwha Techwin, Haydale, IDTechEx, North Carolina Central University & Chaowei Power Ltd, NTNU&CrayoNano, Phantoms Foundation, Southeast University, The Graphene Council, University of Siegen, University of Sunderland and University of Waterloo)
– Extensive thematic workshops in parallel (Materials & Devices Characterization, Chemistry, Biosensors & Energy and Electronic Devices)
– A significant exhibition (Abalonyx, Go Foundation, Grafoid, Group NanoXplore Inc., Raymor | Nanointegris and Suragus GmbH)

As I noted in my 2015 post about Graphene Canada and its conference, the group is organized in a rather interesting fashion and I see the tradition continues, i.e., the lead organizers seem to be situated in countries other than Canada. From the Aug. 31, 2016 news item on Nanotechnology Now,

Organisers: Phantoms Foundation [located in Spain] www.phantomsnet.net
Catalan Institute of Nanoscience and Nanotechnology – ICN2 (Spain) | CEMES/CNRS (France) | GO Foundation (Canada) | Grafoid Inc (Canada) | Graphene Labs – IIT (Italy) | McGill University (Canada) | Texas Instruments (USA) | Université Catholique de Louvain (Belgium) | Université de Montreal (Canada)

You can find the conference website here.

Mechanism behind interaction of silver nanoparticles with the cells of the immune system

Scientists have come to a better understanding of the mechanism affecting silver nanoparticle toxicity according to an Aug. 30, 2016 news item on Nanowerk (Note: A link has been removed),

A senior fellow at the Faculty of Chemistry, MSU (Lomonosov Moscow State University), Vladimir Bochenkov together with his colleagues from Denmark succeeded in deciphering the mechanism of interaction of silver nanoparticles with the cells of the immune system. The study is published in the journal Nature Communications (“Dynamic protein coronas revealed as a modulator of silver nanoparticle sulphidation in vitro”).

‘Currently, a large number of products are containing silver nanoparticles: antibacterial drugs, toothpaste, polishes, paints, filters, packaging, medical and textile items. The functioning of these products lies in the capacity of silver to dissolve under oxidation and form ions Ag+ with germicidal properties. At the same time there are research data in vitro, showing the silver nanoparticles toxicity for various organs, including the liver, brain and lungs. In this regard, it is essential to study the processes occurring with silver nanoparticles in biological environments, and the factors affecting their toxicity,’ says Vladimir Bochenkov.

Caption: Increased intensity of the electric field near the silver nanoparticle surface in the excitation of plasmon resonance. Credit: Vladimir Bochenkov

Caption: Increased intensity of the electric field near the silver nanoparticle surface in the excitation of plasmon resonance. Credit: Vladimir Bochenkov

An Aug. 30, 2016 MSU press release on EurekAlert, which originated the news item, provides more information about the research,

The study is devoted to the protein corona — a layer of adsorbed protein molecules, which is formed on the surface of the silver nanoparticles during their contact with the biological environment, for example in blood. Protein crown masks nanoparticles and largely determines their fate: the speed of the elimination from the body, the ability to penetrate to a particular cell type, the distribution between the organs, etc.

According to the latest research, the protein corona consists of two layers: a rigid hard corona — protein molecules tightly bound with silver nanoparticles, and soft corona, consisting of weakly bound protein molecules in a dynamic equilibrium with the solution. Hitherto soft corona has been studied very little because of the experimental difficulties: the weakly bound nanoparticles separated from the protein solution easily desorbed (leave a particle remaining in the solution), leaving only the rigid corona on the nanoparticle surface.

The size of the studied silver nanoparticles was of 50-88 nm, and the diameter of the proteins that made up the crown — 3-7 nm. Scientists managed to study the silver nanoparticles with the protein corona in situ, not removing them from the biological environment. Due to the localized surface plasmon resonance used for probing the environment near the surface of the silver nanoparticles, the functions of the soft corona have been primarily investigated.

‘In the work we showed that the corona may affect the ability of the nanoparticles to dissolve to silver cations Ag+, which determine the toxic effect. In the absence of a soft corona (quickly sharing the medium protein layer with the environment) silver cations are associated with the sulfur-containing amino acids in serum medium, particularly cysteine and methionine, and precipitate as nanocrystals Ag2S in the hard corona,’ says Vladimir Bochenkov.

Ag2S (silver sulfide) famously easily forms on the silver surface even on the air in the presence of the hydrogen sulfide traces. Sulfur is also part of many biomolecules contained in the body, provoking the silver to react and be converted into sulfide. Forming of the nano-crystals Ag2S due to low solubility reduces the bioavailability of the Ag+ ions, reducing the toxicity of silver nanoparticles to null. With a sufficient amount of amino acid sulfur sources available for reaction, all the potentially toxic silver is converted into the nontoxic insoluble sulfide. Scientists have shown that what happens in the absence of a soft corona.

In the presence of a soft corona, the Ag2S silver sulfide nanocrystals are formed in smaller quantities or not formed at all. Scientists attribute this to the fact that the weakly bound protein molecules transfer the Ag+ ions from nanoparticles into the solution, thereby leaving the sulfide not crystallized. Thus, the soft corona proteins are ‘vehicles’ for the silver ions.

This effect, scientists believe, be taken into account when analyzing the stability of silver nanoparticles in a protein environment, and in interpreting the results of the toxicity studies. Studies of the cells viability of the immune system (J774 murine line macrophages) confirmed the reduction in cell toxicity of silver nanoparticles at the sulfidation (in the absence of a soft corona).

Vladimir Bochenkov’s challenge was to simulate the plasmon resonance spectra of the studied systems and to create the theoretical model that allowed quantitative determination of silver sulfide content in situ around nanoparticles, following the change in the absorption bands in the experimental spectra. Since the frequency of the plasmon resonance is sensitive to a change in dielectric constant near the nanoparticle surface, changes in the absorption spectra contain information about the amount of silver sulfide formed.

Knowledge of the mechanisms of formation and dynamics of the behavior of the protein corona, information about its composition and structure are extremely important for understanding the toxicity and hazards of nanoparticles for the human body. In prospect the protein corona formation can be used to deliver drugs in the body, including the treatment of cancer. For this purpose it will be enough to pick such a content of the protein corona, which enables silver nanoparticles penetrate only in the cancer cell and kill it.

Here’s a link to and a citation for the paper describing this fascinating work,

Dynamic protein coronas revealed as a modulator of silver nanoparticle sulphidation in vitro by Teodora Miclăuş, Christiane Beer, Jacques Chevallier, Carsten Scavenius, Vladimir E. Bochenkov, Jan J. Enghild, & Duncan S. Sutherland. Nature Communications 7,
Article number: 11770 doi:10.1038/ncomms11770 Published  09 June 2016

This paper is open access.