Tag Archives: Institute for Soldier Nanotechnologies

A lobster’s stretch and strength in a hydrogel

An MIT team has fabricated a hydrogel-based material that mimics the structure of the lobster’s underbelly, the toughest known hydrogel found in nature. Credits: Courtesy of the researchers

I love this lobster. In most photos, they’re food. This shows off the lobster as a living entity while showcasing its underbelly, which is what this story is all about. From an April 23, 2021 news item on phys.org (Note: A link has been removed),

A lobster’s underbelly is lined with a thin, translucent membrane that is both stretchy and surprisingly tough. This marine under-armor, as MIT [Massachusetts Institute of Technology] engineers reported in 2019, is made from the toughest known hydrogel in nature, which also happens to be highly flexible. This combination of strength and stretch helps shield a lobster as it scrabbles across the seafloor, while also allowing it to flex back and forth to swim.

Now a separate MIT team has fabricated a hydrogel-based material that mimics the structure of the lobster’s underbelly. The researchers ran the material through a battery of stretch and impact tests, and showed that, similar to the lobster underbelly, the synthetic material is remarkably “fatigue-resistant,” able to withstand repeated stretches and strains without tearing.

If the fabrication process could be significantly scaled up, materials made from nanofibrous hydrogels could be used to make stretchy and strong replacement tissues such as artificial tendons and ligaments.

The team’s results are published in the journal Matter. The paper’s MIT co-authors include postdocs Jiahua Ni and Shaoting Lin; graduate students Xinyue Liu and Yuchen Sun; professor of aeronautics and astronautics Raul Radovitzky; professor of chemistry Keith Nelson; mechanical engineering professor Xuanhe Zhao; and former research scientist David Veysset Ph.D. ’16, now at Stanford University; along with Zhao Qin, assistant professor at Syracuse University, and Alex Hsieh of the Army Research Laboratory.

An April 23, 2021 MIT news release (also on EurekAlert) by Jennifer Chu, which originated the news item, offers an overview of the groundwork for this latest research along with technical detail about the latest work,

Nature’s twist

In 2019, Lin and other members of Zhao’s group developed a new kind of fatigue-resistant material made from hydrogel — a gelatin-like class of materials made primarily of water and cross-linked polymers. They fabricated the material from ultrathin fibers of hydrogel, which aligned like many strands of gathered straw when the material was repeatedly stretched. This workout also happened to increase the hydrogel’s fatigue resistance.

“At that moment, we had a feeling nanofibers in hydrogels were important, and hoped to manipulate the fibril structures so that we could optimize fatigue resistance,” says Lin.

In their new study, the researchers combined a number of techniques to create stronger hydrogel nanofibers. The process starts with electrospinning, a fiber production technique that uses electric charges to draw ultrathin threads out of polymer solutions. The team used high-voltage charges to spin nanofibers from a polymer solution, to form a flat film of nanofibers, each measuring about 800 nanometers — a fraction of the diameter of a human hair.

They placed the film in a high-humidity chamber to weld the individual fibers into a sturdy, interconnected network, and then set the film in an incubator to crystallize the individual nanofibers at high temperatures, further strengthening the material.

They tested the film’s fatigue-resistance by placing it in a machine that stretched it repeatedly over tens of thousands of cycles. They also made notches in some films and observed how the cracks propagated as the films were stretched repeatedly. From these tests, they calculated that the nanofibrous films were 50 times more fatigue-resistant than the conventional nanofibrous hydrogels.

Around this time, they read with interest a study by Ming Guo, associate professor of mechanical engineering at MIT, who characterized the mechanical properties of a lobster’s underbelly. This protective membrane is made from thin sheets of chitin, a natural, fibrous material that is similar in makeup to the group’s hydrogel nanofibers.

Guo found that a cross-section of the lobster membrane revealed sheets of chitin stacked at 36-degree angles, similar to twisted plywood, or a spiral staircase. This rotating, layered configuration, known as a bouligand structure, enhanced the membrane’s properties of stretch and strength.

“We learned that this bouligand structure in the lobster underbelly has high mechanical performance, which motivated us to see if we could reproduce such structures in synthetic materials,” Lin says.

Angled architecture

Ni, Lin, and members of Zhao’s group teamed up with Nelson’s lab and Radovitzky’s group in MIT’s Institute for Soldier Nanotechnologies, and Qin’s lab at Syracuse University, to see if they could reproduce the lobster’s bouligand membrane structure using their synthetic, fatigue-resistant films.

“We prepared aligned nanofibers by electrospinning to mimic the chinic fibers existed in the lobster underbelly,” Ni says.

After electrospinning nanofibrous films, the researchers stacked each of five films in successive, 36-degree angles to form a single bouligand structure, which they then welded and crystallized to fortify the material. The final product measured 9 square centimeters and about 30 to 40 microns thick — about the size of a small piece of Scotch tape.

Stretch tests showed that the lobster-inspired material performed similarly to its natural counterpart, able to stretch repeatedly while resisting tears and cracks — a fatigue-resistance Lin attributes to the structure’s angled architecture.

“Intuitively, once a crack in the material propagates through one layer, it’s impeded by adjacent layers, where fibers are aligned at different angles,” Lin explains.

The team also subjected the material to microballistic impact tests with an experiment designed by Nelson’s group. They imaged the material as they shot it with microparticles at high velocity, and measured the particles’ speed before and after tearing through the material. The difference in velocity gave them a direct measurement of the material’s impact resistance, or the amount of energy it can absorb, which turned out to be a surprisingly tough 40 kilojoules per kilogram. This number is measured in the hydrated state.

“That means that a 5-millimeter steel ball launched at 200 meters per second would be arrested by 13 millimeters of the material,” Veysset says. “It is not as resistant as Kevlar, which would require 1 millimeter, but the material beats Kevlar in many other categories.”

It’s no surprise that the new material isn’t as tough as commercial antiballistic materials. It is, however, significantly sturdier than most other nanofibrous hydrogels such as gelatin and synthetic polymers like PVA. The material is also much stretchier than Kevlar. This combination of stretch and strength suggests that, if their fabrication can be sped up, and more films stacked in bouligand structures, nanofibrous hydrogels may serve as flexible and tough artificial tissues.

“For a hydrogel material to be a load-bearing artificial tissue, both strength and deformability are required,” Lin says. “Our material design could achieve these two properties.”

If you have the time and the interest, do check out the April 23, 2021 MIT news release, which features a couple of informative GIFs.

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

Strong fatigue-resistant nanofibrous hydrogels inspired by lobster underbelly by Jiahua Ni, Shaoting Lin, Zhao Qin, David Veysset, Xinyue Liu, Yuchen Sun, Alex J. Hsieh, Raul Radovitzky, Keith A. Nelson, Xuanhe Zhao. Matter, 2021; DOI: 10.1016/j.matt.2021.03.023 Published April 23, 2021

This paper is behind a paywall.

Smart suits for US soldiers—an update of sorts from the Lawrence Livermore National Laboratory

The US military has funded a program named: ‘Dynamic Multifunctional Material for a Second Skin Program’ through its Defense Threat Reduction Agency’s (DTRA) Chemical and Biological Technologies Department and Sharon Gaudin’s Feb. 20,  2014 article for Computer World offers a bit of an update on this project,which was first reported in 2012,

A U.S. soldier is on patrol with his squad when he kneels to check something out, unknowingly putting his knee into a puddle of contaminants.

The soldier isn’t harmed, though, because he or she is wearing a smart suit that immediately senses the threat and transforms the material covering his knee into a protective state that repels the potential deadly bacteria.

Scientists at the Lawrence Livermore National Laboratory, a federal government research facility in Livermore, Calif., are using nanotechnology to create clothing designed to protect U.S. soldiers from chemical and biological attacks.

“The threat is nanoscale so we need to work in the nano realm, which helps to keep it light and breathable,” said Francesco Fornasiero, a staff scientist at the lab. “If you have a nano-size threat, you need a nano-sized defense.”

Fornasiero said the task is a difficult one, and the suits may not be ready for the field for another 10 to 20 years. [emphasis mine]

One option is to use carbon nanotubes in a layer of the suit’s fabric. Sweat and air would be able to easily move through the nanotubes. However, the diameter of the nanotubes is smaller than the diameter of bacteria and viruses. That means they would not be able to pass through the tubes and reach the person wearing the suit.

However, chemicals that might be used in a chemical attack are small enough to fit through the nanotubes. To block them, researchers are adding a layer of polymer threads that extend up from the top of the nanotubes, like stalks of grass coming up from the ground.

The threads are designed to recognize the presence of chemical agents. When that happens, they swell and collapse on top of the nanotubes, blocking anything from entering them.

A second option that the Lawrence Livermore scientists are working on involves similar carbon nanotubes but with catalytic components in a polymer mesh that sits on top of the nanotubes. The components would destroy any chemical agents they come in contact with. After the chemicals are destroyed, they are shed off, enabling the suit to handle multiple attacks.

An October 6, 2012 (NR-12-10-06) Lawrence Livermore National Laboratory (LLNL) news release details the -project and the proponents,

Lawrence Livermore National Laboratory scientists and collaborators are developing a new military uniform material that repels chemical and biological agents using a novel carbon nanotube fabric.

The material will be designed to undergo a rapid transition from a breathable state to a protective state. The highly breathable membranes would have pores made of a few-nanometer-wide vertically aligned carbon nanotubes that are surface modified with a chemical warfare agent-responsive functional layer. Response to the threat would be triggered by direct chemical warfare agent attack to the membrane surface, at which time the fabric would switch to a protective state by closing the CNT pore entrance or by shedding the contaminated surface layer.

High breathability is a critical requirement for protective clothing to prevent heat-stress and exhaustion when military personnel are engaged in missions in contaminated environments. Current protective military uniforms are based on heavyweight full-barrier protection or permeable adsorptive protective overgarments that cannot meet the critical demand of simultaneous high comfort and protection, and provide a passive rather than active response to an environmental threat.

To provide high breathability, the new composite material will take advantage of the unique transport properties of carbon nanotube pores, which have two orders of magnitude faster gas transport rates when compared with any other pore of similar size.

“We have demonstrated that our small-size prototype carbon nanotube membranes can provide outstanding breathability in spite of the very small pore sizes and porosity,” said Sangil Kim, another LLNL scientist in the Biosciences and Biotechnology Division. “With our collaborators, we will develop large area functionalized CNT membranes.”

Biological agents, such as bacteria or viruses, are close to 10 nanometers in size. Because the membrane pores on the uniform are only a few nanometers wide, these membranes will easily block biological agents.

However, chemical agents are much smaller in size and require the membrane pores to be able to react to block the threat. To create a multifunctional membrane, the team will surface modify the original prototype carbon nanotube membranes with chemical threat responsive functional groups. The functional groups on the membrane will sense and block the threat like gatekeepers on entrance. A second response scheme also will be developed: Similar to how a living skin peels off when challenged with dangerous external factors, the fabric will exfoliate upon reaction with the chemical agent. In this way, the fabric will be able to block chemical agents such as sulfur mustard (blister agent), GD and VX nerve agents, toxins such as staphylococcal enterotoxin and biological spores such as anthrax.

The project is funded for $13 million over five years with LLNL as the lead institution. The Livermore team is made up of Fornasiero [Francesco Fornasiero], Kim and Kuang Jen Wu. Other collaborators and institutions involved in the project include Timothy Swager at Massachusetts Institute of Technology, Jerry Shan at Rutgers University, Ken Carter, James Watkins, and Jeffrey Morse at the University of Massachusetts-Amherst, Heidi Schreuder-Gibson at Natick Soldier Research Development and Engineering Center, and Robert Praino at Chasm Technologies Inc.

“Development of chemical threat responsive carbon nanotube membranes is a great example of novel material’s potential to provide innovative solutions for the Department of Defense CB needs,” said Tracee Harris, the DTRA science and technology manager for the Dynamic Multifunctional Material for a Second Skin Program. “This futuristic uniform would allow our military forces to operate safely for extended time periods and successfully complete their missions in environments contaminated with chemical and biological warfare agents.”

The Laboratory has a history in developing carbon nanotubes for a wide range of applications including desalination. “We have an advanced carbon nanotube platform to build and expand to make advancements in the protective fabric material for this new project,” Wu said.

The new uniforms could be deployed in the field in less than 10 years. [emphasis mine]

Since Gaudin’s 2014 article quotes one of the LLNL’s scientists, Francesco Fornasiero, with an estimate for the suit’s deployment into the field as 10 – 20 years as opposed to the “less than 10 years” estimated in the news release, I’m guessing the problem has proved more complex than was first anticipated.

For anyone who’s interested in more details about  US soldiers and nanotechnology,

  • May 1, 2013 article by Max Cacas for Signal Online provides more details about the overall Smart Skin programme and its goals.
  • Nov. 15, 2013 article by Kris Walker for Azonano.com describes the Smart Skin project along with others including the intriguingly titled: ‘Warrior Web’.
  • website for MIT’s (Massachusetts Institute of Technology) Institute for Soldier Nanotechnologies Note: The MIT researcher mentioned in the LLNL news release is a faculty member of the Institute for Soldier Nanotechnologies.
  • website for the Defense Threat Reduction Agency

Introduction to nanotechnology with a focus on military, security, and surveillance applications

SIGNAL, a magazine produced by AFCEA INTERNATIONAL (Armed Forces Communications and Electronics Association) has published in its December 2013 issue (or you can try this Table of Contents page) an introductory article to the topic in what appears to be a special section devoted to nanotechnology. The Dec. 1, 2013 article by Rita Boland (h/t Dec. 13, 2013 Azonano news item) does a good job of presenting a ‘big picture’ approach including nonmilitary and military  nanotechnology applications  by interviewing the main players in the US,

Nanotechnology is the new cyber, according to several major leaders in the field. Just as cyber is entrenched across global society now, nano is poised to be the major capabilities enabler of the next decades. Expert members from the National Nanotechnology Initiative representing government and science disciplines say nano has great significance for the military and the general public.

According to the initiative, its aim is to move discoveries from the laboratory into products for commercial and public benefit; encourage students and teachers to become involved in nanotechnology education; create a skilled work force and the supporting infrastructure and tools to advance nanotechnology; and support responsible development. The initiative involves more than two dozen government agencies, industry, academic partners and international participants.

For anyone who’s interested in nanotechnology but doesn’t want to get particularly technical about it, I recommend this article as a good overview of the possibilities being entertained by individuals presumably familiar with the current state of research.

I  also found this to be an opportunity to find out about SIGNAL and AFCEA. Starting with SIGNAL, (from the About SIGNAL page),,

Founded in 1946, SIGNAL Magazine covers the latest trends and techniques in topics that include C4ISR, information security, intelligence, electronics, homeland security, cyber technologies, cloud computing and all the programs or solutions that build on these and related disciplines.

Our aim is to deliver useful and innovative information that enables our readers to remain up to date on technology easier, to understand military, government and industry needs faster, and to excel in supporting global security through knowledge.

We’re More than a Magazine, We’re AFCEA

As the official publication of AFCEA, a well-known and respected organization that also has been serving government and military since 1946, SIGNAL is unique from other defense and government magazines and websites.

We are the only media group that consistently reaches the entire AFCEA community, often with access to news faster. Top level leaders, managers, technical experts and the industry that supports them trust the AFCEA brand for accurate, unbiased and ethical reporting.

As for AFCEA, I was quite fascinated to find out that it was founded by David Sarnoff for reasons I will mention after this excerpt from AFCEA’s About page,

Mission Statement

AFCEA is a 501(c)(6) non-profit  international organization that serves its members by providing a forum for the ethical exchange of information. AFCEA is dedicated to increasing knowledge through the exploration of issues relevant to its members in information technology, communications, and electronics for the defense, homeland security and intelligence communities.

AFCEA History

AFCEA’s founders, a group of communicators led by David Sarnoff, experienced first-hand how open dialogue and strong relationships between government and industry in times of peace can help ensure effective communications during wartime. In 1946, they established AFCEA from the U.S. Veterans Signal Association and the American Signal Corps Association with the goal of promoting communication, dialogue, and an open and ethical exchange of information between the public and private sectors. As the Association’s outreach has broadened, this goal remains the pillar of AFCEA International.

I first heard David Sarnoff’s name in an undergraduate communications lecture about the Titanic. Here’s more from the David Sarnoff Wikipedia essay (Note: All links have been removed),

David Sarnoff (Belarusian: Даві́д Сарно́ў, Russian: Дави́д Сарно́в, February 27, 1891 – December 12, 1971) was a Belarusian-born American businessman and pioneer of American radio and television. Throughout most of his career he led the Radio Corporation of America (RCA) in various capacities from shortly after its founding in 1919 until his retirement in 1970.

He ruled over an ever-growing telecommunications and consumer electronics empire that included both RCA and NBC, and became one of the largest companies in the world. Named a Reserve Brigadier General of the Signal Corps in 1945, Sarnoff thereafter was widely known as “The General.”[1]

Sarnoff is credited with Sarnoff’s law, which states that the value of a broadcast network is proportional to the number of viewers.

David Sarnoff was born to a Jewish family in Uzlyany, a small town in Belarus, to Abraham and Leah Sarnoff. Abraham Sarnoff emigrated to the United States and raised funds to bring the family. Sarnoff spent much of his early childhood in a cheder studying and memorizing the Torah. He immigrated with his mother and three brothers and one sister to New York City in 1900, where he helped support his family by selling newspapers before and after his classes at the Educational Alliance. In 1906 his father became incapacitated by tuberculosis, and at age 15 Sarnoff went to work to support the family.[2] He had planned to pursue a full-time career in the newspaper business, but a chance encounter led to a position as an office boy at the Commercial Cable Company. When his superior refused him unpaid leave for Rosh Hashanah, he joined the Marconi Wireless Telegraph Company of America on September 30, 1906, and started a career of over 60 years in electronic communications.

Over the next 13 years Sarnoff rose from office boy to commercial manager of the company, learning about the technology and the business of electronic communications on the job and in libraries. He also served at Marconi stations on ships and posts on Siasconset, Nantucket and the New York Wanamaker Department Store. In 1911 he installed and operated the wireless equipment on a ship hunting seals off Newfoundland and Labrador, and used the technology to relay the first remote medical diagnosis from the ship’s doctor to a radio operator at Belle Isle with an infected tooth. [emphasis mine] The following year, he led two other operators at the Wanamaker station in an effort to confirm the fate of the Titanic.[3] [emphasis mine] Sarnoff falsely advanced himself both as the sole hero who stayed by his telegraph key for three days to receive information on the Titanic’s survivors and as the prescient prophet of broadcasting who predicted the medium’s rise in 1916.[2]

Due to its proximity to Europe, Newfoundland played a significant historical role in both communications and transportation technology.

Getting back to ACFEA, there are three Canadian chapters but only the Ottawa chapter appears to be active as of Dec. 18, 2013.

One final note,, in writing this piece I was reminded of the Massachusetts Institute of Technology’s Institute for Soldier Nanotechnologies (last mentioned here in a May 1, 2012 posting about sniffing overripe fruit.