April, 2021
UMass Amherst Team Discovers How to Use Elasticity to Control the Positions of Solid Micro-plates on Curved 2D Fluids

A team of polymer science and engineering researchers at the University of Massachusetts Amherst has demonstrated for the first time that the positions of tiny, flat, solid objects integrated in nanometrically thin membranes – resembling those of biological cells – can be controlled by mechanically varying the elastic forces in the membrane itself. This research milestone is a significant step toward the goal of creating ultrathin flexible materials that self-organize and respond immediately to mechanical force.

The team has discovered that rigid solid plates in biomimetic fluid membranes experience interactions that are qualitatively different from those of biological components in cell membranes. In cell membranes, fluid domains or adherent viruses experience either attractions or repulsions, but not both, says Weiyue Xin, lead author of the paper detailing the research, which recently appeared in Science Advances. But in order to precisely position solid objects in a membrane, both attractive and repulsive forces must be available, adds Maria Santore, a professor of polymer science and engineering at UMass.

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February, 2021
UMass Amherst Researchers Discover Materials Capable of Self-Propulsion: Research highlights how shape and environment can cause materials to move without motors or hands

Imagine a rubber band that was capable of snapping itself many times over, or a small robot that could jump up a set of stairs propelled by nothing more than its own energy. Researchers at the University of Massachusetts Amherst have discovered how to make materials that snap and reset themselves, only relying upon energy flow from their environment. The discovery may prove useful for various industries that want to source movement sustainably, from toys to robotics, and is expected to further inform our understanding of how the natural world fuels some types of movement.

Al Crosby, a professor of polymer science and engineering in the College of Natural Sciences at UMass Amherst and Yongjin Kim, a graduate student in Crosby’s group, along with visiting student researcher Jay Van den Berg from Delft University of Technology in the Netherlands, uncovered the physics during a mundane experiment that involved watching a gel strip dry. The researchers observed that when the long, elastic gel strip lost internal liquid due to evaporation, the strip moved. Most movements were slow, but every so often, they sped up. These faster movements were snap instabilities that continued to occur as the liquid evaporated further. Additional studies revealed that the shape of the material mattered, and that the strips could reset themselves to continue their movements.

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December, 2020
Six UMass Amherst Faculty Recognized Among 2020 World’s Most Highly Cited Researchers

Six campus researchers in the College of Natural Sciences (CNS) at the University of Massachusetts Amherst have been recognized among the world’s most highly cited researchers in 2020 by London-based Clarivate Analytics, owner of the Web of Science. They have consistently had high citation counts over a decade.

Now in its seventh year, the citation analysis identifies influential researchers as determined by their peers around the world. They are judged to be influential, and their citation records are seen as “a mark of exceptional impact,” the company says.

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December, 2020
UMass Amherst Polymer Scientist Awarded NSF CAREER Grant: Katsumata grew up appreciating historic connection between UMass and Hokkaido U.

Polymer scientist Reika Katsumata at the University of Massachusetts Amherst recently was chosen to receive a prestigious 2021 Faculty Early Career Development (CAREER) award from the National Science Foundation (NSF). The five-year, $595,000 grant will support her investigations into fundamental problems bridging polymer science and engineering to better understand how different-sized molecules move in relationship to each other when they are heated.

As she explains, understanding such multi-scale polymer dynamics “is very important to how you form and shape polymers for use at room temperature. We are trying to understand what is going on at the molecular level. It’s a long-standing, sixty-year-old problem.”

Surprisingly, the molecular details are not known, Katsumata adds. “Every day I learn how little we know about materials and their relationships.” In particular, these dynamics are not straightforward for nanocomposites, she notes, and her lab will bring new knowledge at this level. Also, she has special expertise in fluorescence techniques that she will use in a series of experiments that for the first time combine two distinct methods to achieve new breakthroughs.

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September, 2020
Research Shows How to Imitate Natural Spring-loaded Snapping Movement Without Losing Energy UMass Amherst materials scientists outline fundamental physics of bending into a snap

Venus flytraps do it, trap-jaw ants do it, and now materials scientists at the University of Massachusetts Amherst can do it, too – they discovered a way of efficiently converting elastic energy in a spring to kinetic energy for high-acceleration, extreme velocity movements as nature does it.

In the physics of human-made and many natural systems, converting energy from one form to another usually means losing a lot of that energy, say first author Xudong Liang and senior researcher Alfred Crosby. “There is always a high cost, and most of the energy in a conversion is lost,” Crosby says. “But we have discovered at least one mechanism that helps significantly.” Details are in Physical Review Letters.

Using high-speed imaging, Liang and Crosby measured in fine detail the recoiling, or snapping, motion of elastic bands that can reach accelerations and velocities similar to many of the natural biological systems that inspired them. By experimenting with different elastic band conformations, they discovered a mechanism for imitating ant and flytrap fast-motion, high-power impulse events with minimal energy loss.

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September, 2020
Early Detection of Soil-Surface Ozone Can Help Prevent Damage to Grape Vines and Apple Trees UMass Amherst materials chemists develop a durable leaf “tattoo” for monitoring

Farmers and fruit growers are reporting that climate change is leading to increased ozone concentrations on the soil surface in their fields and orchards – an exposure that can cause irreversible plant damage, reduce crop yields and threaten the food supply, say materials chemists led by Trisha Andrew at the University of Massachusetts Amherst.

Writing in Science Advances, co-first authors Jae Joon Kim and Ruolan Fan show that the Andrew lab’s method of vapor-depositing conducting polymer “tattoos” on plant leaves can allow growers to accurately detect and measure such ozone damage, even at low exposure levels. Their resilient polymer tattoos placed on the leaves allow for “frequent and long-term monitoring of cellular ozone damage in economically important crops such as grapes and apples,” Andrew says.

They write, “We selected grapes (Vitis vinifera L.) as our model plant because the fruit yield and fruit quality of grapevines decrease significantly upon exposure to ground level ozone, leading to significant economic losses.” Ground-level ozone can be produced by the interaction between the nitrates in fertilizer and the sun, for example.

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September, 2020
Grason, Greg
Greg Grason Named Fellow of the American Physical Society

Professor Greg Grason, a theoretical polymer scientist in polymer science and engineering, has been elected a Fellow of the American Physical Society (APS) by its Council of Representatives this month as recommended by the society’s Division of Polymer Physics

The society’s announcement states that the selection as an APS Fellow is a “prestigious recognition by your peers of your outstanding contributions to physics.” In the award citation, Grason is recognized “for elucidation of the role of molecular geometric packing frustration on the fundamental physics for the selection of complex self-assembled phases.”

Grason says, “I’m very honored to named APS fellow and humbled to be able to join the ranks of the many of outstanding colleagues at UMass and elsewhere who have also received this recognition.”

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June, 2020
Russell Honored with Shull Prize in Neutron Science

Professor Thomas P. Russell, polymer science and engineering, was recently honored by the Neutron Scattering Society of America with its highest honor, the Clifford G. Shull Prize in Neutron Science, for “his pivotal role in the application of neutron reflectivity and small-angle neutron scattering to polymer science and his important work on behalf of the neutron scattering community.”

The prize is named in honor of Shull, who received the Nobel Prize in 1994 with Bert Brockhouse for seminal developments in the field of neutron science.

Russell says, “I was truly honored with this recognition and was happy to have been able to have made a significant contribution to the field that has advanced our understanding of long-chain molecules in thin film and at surfaces and interfaces. It was equally rewarding to have worked with outstanding scientists at Argonne National Laboratory (ANL) and the National Institute of Standards and Technology (NIST) and a talented group of post-doctoral fellows and graduate students.”

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June, 2020
Global Team Develops Open-source N95 Respirator: UMass Amherst lab produces 3D prototype pieces for Holyoke design consultancy

In one of the latest COVID-19 response projects at the University of Massachusetts Amherst, the Advanced Digital Design and Fabrication (ADDFab) laboratory is collaborating with a global network of design, engineering and manufacturing experts to help develop an open-source N95 face mask.

ADDFab, one of the core facilities at UMass’s Institute for Applied Life Sciences, has been rapidly preparing 3D prints of prototype parts and molds for Cofab Design in Holyoke. Cofab business partner and design engineer Aaron Cantrell is one of primary leaders of the Open Standard Respirator (OSR) project, a“nonprofit effort to broaden protective equipment supply for COVID-19 and beyond.” The other leaders are biomechatronics engineer Matt Carney of the MIT Media Lab Biomechatronics Group and Philip Brown, assistant professor of biomedical engineering at Wake Forest University Baptist Medical Center.

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May, 2020
Experimental and Theoretical Physicists Clarify an Old Muddle

Recent correspondence in “Nature Materials” by a team of campus researchers answers a long-time question that experimental physicist Narayanan Menon says is “one of those things you should be able to look up in a textbook, a very basic question. But when you do look into the literature, there’s confusion, and it has been going on for decades. Our work isn’t screaming ‘new discovery,’ but this basic question is what we have clarified.”

In addition to Menon, the team included theoretical physicist Benny Davidovitch, polymer scientist Thomas Russell and a former UMass postdoctoral physics researcher, Deepak Kumar. He led the experiments and analysis for the report and is now starting as a new faculty member at the Indian Institute of Technology, Delhi.

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