UD Professor Laure Kayser received an NSF CAREER award to further her group’s materials science research
Whether it’s a smartwatch that can detect irregular heartbeats or a continuous glucose monitor, electronics that can interface with biology have already started to revolutionize the future of healthcare. But while the potential of these devices is far-reaching, the materials that make up future bioelectronics have to meet several different criteria — such as not causing damage or irritation to skin and avoiding toxic metals, for example.
Creating new organic, biocompatible materials that can interface with living systems is Laure Kayser, assistant professor in the Department of Materials Science and Engineering at the University of Delaware’s College of Engineering. Now, thanks to an award from the National Science Foundation (NSF), she and members of her lab will continue their fundamental research on a new class of polymers that could pave the way for future applications in human health.
The Kayser Lab specializes in designing, synthesizing and characterizing new plastics and polymers that can conduct electricity while safely interfacing with living systems. By working at the intersection of chemistry, polymer science and materials engineering, her lab is able to develop innovative design and synthesis approaches for creating new types of plastic materials.
Kayser, who holds a joint appointment in the Department of Chemistry and Biochemistry in the College of Arts and Sciences, said that what sets her group apart from others in the field of organic bioelectronics is a strong foundation in organic chemistry and their ability to make any material they want instead of only being limited to what’s currently available.
“We do modern chemistry, including chemistry that is not necessarily typically used in the field, and apply it to materials science,” said Kayser. “Because we have a background in chemistry and synthesis, we can make any material, characterize it, establish structure-property relationships and tailor it so the material can be interfaced with biology.”
Design rules for electronic highways and ionic waves
Starting in July, Kayser’s group will be investigating a new type of organic bioelectronic material. With a five-year, $654,206 Faculty Early Career Development Program (CAREER) award from NSF, her lab will study the fundamental properties of polymers that have properties inspired by living systems and also meet the criteria for being able to be incorporated into bioelectronic devices.
For this project, the lab will be studying derivatives of PEDOT:PSS. This polymer belongs to a class of materials known as organic mixed ionic electronic conductors, which have the unique ability to conduct both electrons and ions.
This is a necessary yet difficult to achieve property for bioelectronics: Typical electronic devices, such as laptops or cell phones, use electrons to transmit signals, while systems in biology, such as nerves, use ions. This difference in communication methods makes it difficult to “translate” signals from electronic devices into ones that a cell or organ can interpret.
Laure Kayser (right), an assistant professor in the College of Engineering’s Department of Materials Science and Engineering and doctoral candidate Vidhika Damani working in the lab with PEDOT:PSS, a polymer with the unique ability to conduct both electrons and ions.
There are also engineering challenges in creating this class of materials, Kayser explained. “There are very different design rules whether you want a material to be an electronic conductor or an ionic conductor,” she said. “For example, electronic conductors are very well ordered — like a highway for electrons to travel down. But if you want to make a good ionic conductor, ions usually like to be on a floppy, almost liquid environment, so more like a wave.”
Members of the Kayser lab, including doctoral students Chun-Yuan Lo, Vidhika Damani, Dan My Nguyen, and Elorm Awuyah, were instrumental in getting preliminary results for the proposed research. The team recently published a paper in Polymer Chemistry (which was also featured on the journal’s May 21st 2022 cover), where they determined the role of different chemical properties in PEDOT:PSS and how they could be changed to make the material more efficient in bioelectronic devices, a key finding that showcased how the group’s expertise in this field could be applied to PEDOT:PSS.
Through the CAREER award, the lab will continue studying derivatives of PEDOT:PSS to gain a solid, fundamental understanding of how to control both electronic and ionic conduction. The long-term goal is to develop design rules for fabricating bioelectronic devices with this class of materials in the future.
“Our lab’s focus is to understand deeply how chemical structures affect the electronic properties of those materials,” said Kayser. “Through this grant, we’re going to learn a lot about these materials — some of these ideas might fail, but we’ll learn something along the way.”
Materials science outreach and education
With this CAREER award, Kayser will also be leading different outreach and educational initiatives for both high school students and undergraduates.
Part of this work will include connecting with female students at local high schools. This will be done through both a materials science-focused outreach program as well as a mentorship program, where graduate students and senior undergraduate students will be paired with high school students to provide support throughout the college application process.
Researchers in Laure Kayser’s lab recently published a paper in Polymer Chemistry (featured on the May 21st 2022 cover) where they determined the role of different chemical properties in PEDOT:PSS and how they can be changed to make the material more efficient in bioelectronic devices.
Kayser will also be working with Sheldon Hewlett, an assistant professor who leads instruction and teaching in the materials science and engineering department, on integrating research into undergraduate curriculum. With support from the CAREER award, junior year materials science students will conduct a polymerization of PEDOT:PSS, including synthesis, purification and characterization, as part of a laboratory module. There will also be opportunities for students to address additional research questions during the course module, as well as funded research programs for those who are interested in carrying their work into the summer.
Along with introducing students to the process of polymerization, Hewlett added that this project will allow students to work with a class of materials in a laboratory course that they are likely to encounter in their career. “Not only will this award give us an opportunity for students to do real research, but it also provides students with a novel material system to work with,” said Hewlett. “You don’t see a lot of lab courses working with these polymers at this level — of making a material from start to finish, and then characterizing it afterwards.”
Making new discoveries through ‘great fundamental science’
“Chemistry will be central to the discoveries that Laure Kayser’s research group will advance on plastics and other polymeric materials through this NSF CAREER award,” said Joel Rosenthal, professor and chair of the Department of Chemistry and Biochemistry. “Rather than simply tweaking or studying materials that already exist, the Kayser lab is adept at leveraging synthetic chemistry to discreetly control the composition, and by extension, the properties of new polymers for various applications, including bioelectronics. I’m incredibly excited to see how her group’s work will continue to develop over the next several years.”
Joshua Zide, professor and chair of the Department of Materials Science and Engineering, added, “Professor Kayser is a fantastic contributor to the Materials Science and Engineering Department, and we are lucky to have her. Her research translates the chemistry to myriad important applications, and the perspective she brings is a huge benefit to the whole department.”
While Kayser is excited about the potential of her research to potentially impact a wide range of applications and fields, she is also looking forward to the “great fundamental science” that this CAREER award will enable her group to do.
“It’s a relatively hot area that is going to continue growing, so it’s a good place for us to be leading the pack,” she said. “I’m hoping that by learning more about the fundamentals of these materials, it might inspire others to explore different molecular designs and how they can be translated into devices. Overall, I think we’re going to make lots of really cool discoveries.”
Article by Erica K. Brockmeier | Photos by Evan Krape | March 03, 2023
Esteemed engineer to travel the world to advance science and technology cooperation with U.S.
LaShanda Korley, Distinguished Professor of Materials Science and Engineering and Chemical and Biomolecular Engineering at the University of Delaware, has been appointed a U.S. Science Envoy for 2023. The announcement was made by the U.S. Department of State on Tuesday, Dec. 6.
Through the Science Envoy Program, eminent U.S. scientists and engineers leverage their expertise and networks to forge connections and identify opportunities for sustained international cooperation, championing innovation and demonstrating America’s scientific leadership and technical ingenuity.
Korley is among seven distinguished scientists who will begin service as U.S. Science Envoys in January 2023. Like their 23 predecessors, these esteemed scientists are approved by the Secretary of State and will engage internationally at the citizen and government levels to enhance relationships between other nations and the United States, develop partnerships and improve collaboration.
According to the U.S. Department of State, Science Envoys leverage their international leadership, influence and expertise in priority countries and regions to advance solutions to shared challenges. They travel as private citizens and help inform the State Department, other U.S. government agencies and the scientific community about opportunities for science and technology cooperation.
Korley is a global leader in applying biologically inspired principles and approaches to the sustainable use of polymer-based materials, including plastics. She is the director of the Center for Plastics Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy that is working to chemically transform plastic waste — a pollution problem plaguing the world — into fuels, lubricants and other valuable products.
She also leads Bio-Inspired Materials and Systems, a global project funded through the National Science Foundation’s Partnerships for International Research and Education, which aims to develop programmable materials for soft robotic systems, and she is co-director of the UD Center for Hybrid, Active, and Responsive Materials, an NSF Materials Research and Science Center that is driving materials innovation in fields ranging from biomedicine to cybersecurity.
The recipient of numerous awards and honors, Korley is a fellow of the American Physical Society, the American Chemical Society Division of Polymeric Materials: Science and Engineering, and the American Institute for Medical and Biological Engineering. She received her bachelor’s degrees from Clark Atlanta University and the Georgia Institute of Technology and her doctorate from the Massachusetts Institute of Technology. She completed postdoctoral studies at both MIT and Cornell.
Joining Korley in the 2023 cohort of U.S. Science Envoys are Drew Harvell (Cornell University), Jessica Gephart (American University), Christine Kreuder Johnson (University of California, Davis), Prineha Narang (UCLA), Frances Seymour ( World Resources Institute) and Kyle Whyte (University of Michigan). The State Department announcement has more information about the other envoys.
Article by Tracey Bryant Photo illustration by Jeffrey C. Chase December 06, 2022
UD Engineering’s LaShanda Korley elected as a 2022 American Physical Society Fellow
University of Delaware College of Engineering Distinguished Professor LaShanda Korley has been elected as a 2022 Fellow of the American Physical Society (APS) “for innovative bio-inspired strategies to control architecture, assembly, and mechanics of soft material systems.”
Korley, who holds appointments in the departments of Materials Science and Engineering and Chemical and Biomolecular Engineering, and her research group take inspiration from nature to design new polymers using innovative molecular-level design strategies and manufacturing approaches. Korley is also the director of UD’s Center for Plastics Innovation (CPI) and the co-director of the Center for Hybrid, Active, and Responsive Materials (CHARM).
By studying the architectures and design rules used by the natural world, Korley’s research helps materials scientists bridge the gap between fabricating simple, sustainable materials that also have a wide array of complex functions and downstream applications.
“Our group has a strategic vision on the interconnection between molecular design, engineering and materials science to design functional polymers,” Korley said about what makes her group unique. “We tackle the full macromolecular design spectrum from chemistry to processing to impact polymer architecture and function.”
Among her group’s long-standing research projects is their innovative work on spider silk, a biological material that Korley says continues to be a rich source of inspiration due to its unique and tunable mechanical behavior. Her group is also exploring the possibilities of using lignin, an organic polymer that is a component of tree bark, as a building block for plastics in lieu of petroleum-based products, as well as connecting polymeric features to new deconstruction and upgrading strategies for plastics waste.
“Professor Korley has made substantial contributions to understanding the polymer physics of network-forming systems through an exquisite mix of detailed polymer synthesis, materials characterization, and polymer processing,” said Thomas Epps, III, the Allan and Myra Ferguson Distinguished Professor of Chemical and Biomolecular Engineering, who nominated Korley for this award. “Her activities bring actionable insights that promote new applications of polymeric materials.”
Each year, APS, a scholarly society and publisher for the physics community, recognizes less than 1% of its members through the APS Fellowship Program. Korley’s outstanding contributions in bio-inspired materials science research was recognized by the Division of Polymer Physics, and she will receive her certificate at the APS annual meeting in March 2023.
“As a chemical engineer who works on polymer science and engineering, fundamental physical principles are what’s driving the design, so physics and engineering go hand in hand,” Korley said of being recognized by the APS. “If I’m designing a material at the molecular level, I have to understand and apply these underlying polymeric physics concepts.”
Along with her election as an APS Fellow, Korley is also a 2022 ACS Division of Polymer Materials Science and Engineering (PMSE) Fellow, a recipient of the 2021 AIChE Minority Affairs Committee (MAC) Gerry Lessells Award, was named a 2020 American Institute for Medical and Biological Engineering (AIMBE) Fellow, and received the 2019 National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) Lloyd N. Ferguson Young Scientist Award.
“I am extremely pleased to see Professor Korley receive this well-deserved recognition, joining other Fellows within the department,” said Joshua Zide, professor and chair of the Department of Materials Science and Engineering. “Her work serves as an inspiration to her colleagues, and we are always happy to see others also recognize her impact in the world. Locally, we appreciate that she is also an outstanding citizen of the department, and the students appreciate her teaching and mentorship.”
Referring to what the future holds for her group, Korley said, “There’s still more molecular engineering to do, and lots of questions driven by trying to understand concepts from nature that we see around us and that inspires us. Overall, I feel honored by this recognition from APS — not just for myself, but for my students, because they are the ones that believe in our lab’s large-scale vision and drive the innovation that makes this work possible.”
Article by Erica K. Brockmeier | Photo by Kathy F. Atkinson | October 19, 2022
Joshua Zide was chosen for the 2022 Outstanding Doctoral Advising and Mentoring Award
Achieving a doctoral degree is a strenuous and demanding business that can strain every neuron a student can muster.
Having an adviser of the caliber of Joshua Zide, professor of materials science and engineering, who brings a unique blend of service, compassion and research excellence to the task, can make a profound difference for students.
For his commitment to student success professionally and personally, Zide has won the University of Delaware’s 2022 Outstanding Doctoral Advising and Mentoring Award.
The award is given annually to a faculty member whose dedication and commitment to excellence in graduate training have made “a significant contribution to the quality of life and professional development of graduate students” at UD.
“Josh’s style of mentorship is best captured by the concept of servant leadership,” doctoral student James Bork wrote in his letter of nomination, “which constitutes an inversion of the traditional boss/subordinate hierarchy. He believes that his role is to support us and our work, not the inverse. This is well illustrated by his repeated emphasis to us that ‘You don’t work for me. Instead, I work with you.’”
Zide heard something similar when he was a student and realized the impact that approach had on him. He was at a project review meeting and the comment came from his doctoral adviser — Prof. Art Gossard at the University of California, Santa Barbara.
“He said, ‘I’m Art Gossard and I work with Joshua,’” Zide recalled. “Not ‘I advise Joshua’ or ‘Joshua works for me.’ Art is a famous, well-respected scientist who has had an incredibly distinguished career, and that single comment made me realize that the framing really matters and that I was the owner of my effort. I knew that was the kind of adviser I wanted to be.”
He has achieved that goal, his students say. They have high confidence both in his scholarship and the values he underscores as they work together.
“Josh’s unique student-oriented approach fosters an almost parental relationship with us students,” Bork wrote, “one where not only is our performance as a researcher important, but also our mental and emotional wellbeing.”
Those qualities were especially welcome as the emergence of the COVID-19 pandemic bit into everyone’s lives, exacerbating already difficult conditions, Bork said. Zide offered assistance at every team meeting and kept in touch often by text or other messages to help students stay connected and navigate the changes, he said.
Zide customizes his advising methods to meet student’s different needs, doctoral student Lauren Nowicki McCabe said in her nomination letter.
“This could be either weekly or as-needed individual meetings, offering extra practice on presentations, extra attention given to editing student writing, tutoring in concepts from classes he didn’t even teach, running down to the lab as a sanity check during equipment maintenance, and the list goes on and on,” she wrote.
McCabe also noted Zide’s “dad jokes” — “which always helps everyone roll their eyes and feel at ease” — and the occasional visits of Zide’s dogs to help students de-stress.
“He has cheered with me when my experiments work, knocked on wood for the ones that we’re excited about and groaned with me when things went disastrously wrong,” McCabe wrote.
A student who was not among his advisees but took Zide’s course on Epitaxial Growth and Band Engineering in 2019, wrote that the experience was not only outstanding academically but also transformative personally.
Zide’s “expert guidance helped me to navigate through academic struggles and his kindred spirit and kindness helped me to regain my self-esteem and confidence,” wrote Kazy Fayeen Shariar, now an engineer with GlobalFoundries. “His mentoring and guidance ultimately helped me reach graduation.”
Zide’s research in nanoscale engineering, specifically in the use of molecular beam epitaxy for engineering new semiconductors and nanocomposites, has been recognized with awards throughout his career. Last year, for example, he was elected a fellow of AVS, recognizing sustained and outstanding contributions in materials, interfaces and processes.
As he excels in these endeavors, he brings students into that environment of excellence, helping them to hone their research skills, find their footing as scientists in advanced engineering and navigate the many challenges that arise along the way.
“I think that I excel in my research precisely because I enable my students to bring their best selves to their work,” he said. “Time management is, of course, always a struggle, but everyone has to choose what’s important to them and for me it’s making sure to look after people. Mostly, I can’t imagine someone coming to me and saying they’re in a crisis and saying, ‘Sorry, not my problem.’”
Bork said making time to help and care for others is central to Zide’s approach to research and life.
“He frequently encourages us to be ‘good neighbors’ to others and insists that time spent helping others is equally as important as time making progress on my research,” Bork said. “And while Josh would be slow to claim credit for the accomplishments of his students, it’s his example from which I’ve learned how to nurture my professional life without losing sight of the bigger picture and his supportiveness that enables me to do so.”
Zide has chaired seven doctoral thesis committees, two master’s thesis committees and served as a member of 45 other thesis committees in materials science and engineering and across campus.
His students have earned many significant awards, including competitive doctoral and graduate fellowships and awards for service, research, teaching and professional development.
“This impressive number of awards for his current and past students clearly is indication of his strong mentorship and energetic support of his students as they work in the classroom and laboratory under his leadership,” wrote Darrin Pochan, chair and professor in the Department of Materials Science and Engineering, in his letter of nomination. “His students have also been excellent citizens of the department in both explicit service capacity as well as implicit support of the welcoming and vigorous culture.”
In addition to his research, teaching and advising work, Zide directs the Materials Science and Engineering Graduate Program, was co-founder of the popular “Words for Nerds” program that aims to help students excel in science communication, and is co-director of the Materials Growth Facility. He also serves as associate editor of the Journal of Vacuum Science and Technology.
Zide, who joined the UD faculty in 2007, earned his bachelor’s degree at Stanford University and his doctorate at the University of California, Santa Barbara.
Professors Chen, Day, Pochan and Wang recognized for excellence in medical and biological engineering
Four faculty members from the University of Delaware’s College of Engineering have been recognized by the American Institute for Medical and Biological Engineering (AIMBE) as members of the organization’s 2022 College of Fellows.
Gore Professor of Chemical Engineering Wilfred Chen, Biomedical Engineering Associate Professor Emily Day, Department of Materials Science and Engineering Chair and Professor Darrin Pochan and Mechanical Engineering Professor Liyun Wang join 149 other fellows recognized this year by the AIMBE for “distinguished and continuing achievements in medical and biological engineering.”
“The election of four College of Engineering faculty members as fellows of the AIMBE speaks to the outstanding talent that can be found right here at the University of Delaware,” said Dean Levi Thompson. “Their work to tackle the grandest challenges we face globally has the full support of their colleagues and this College, and I’m proud to see the wave of new innovations happening in laboratories right here in Delaware.”
Election as an AIMBE Fellow is among the highest recognitions medical and biological engineers can receive, and this cohort of fellows highlights the importance of diversity in disciplines required to advance the future of these research areas. According to an AIMBE press release, only the top 2% of medical and biological engineers are elected to the College of Fellows. Previous Fellows include Nobel prize winners, over 200 members of the National Academy of Engineering and recipients of many other accolades and accomplishments.
The honor recognizes those who have made significant contributions to “engineering and medicine research, practice or education” and to “the pioneering of new and developing fields of technology, making major advancements in traditional fields of medical and biological engineering, or developing/implementing innovative approaches to bioengineering education,” according to the AIMBE.
The 2022 Fellows will be formally recognized at a virtual ceremony on Friday, March 25.
Meet the Fellows
Wilfred Chen, an expert in protein engineering and synthetic biology and professor in the Department of Chemical and Biomolecular Engineering, joined UD faculty in 2011 after spending 16 years as a professor at the University of California, where he also served as presidential chair of chemical engineering. He has served in editorial roles for multiple journals, and continues to serve as an editor, associate editor or on the editorial board of several publications and has written 250 peer-reviewed studies that have been cited over 20,000 times.
Chen described his work as looking at proteins like individual LEGO blocks and finding ways to put them together. “If I can do it correctly, they can perform the precise functions I want them to do,” he said.
The complex biomolecular engineering Chen undertakes in his lab could have broad implications on a more renewable-based “green economy,” such as finding biological systems to replace petroleum-derived chemicals, as needed to swiftly reduce greenhouse gas emissions to avoid future climate disasters. His work could also improve cancer treatment, but more work needs to be done before a new biological-based option can replace painful chemotherapy treatments.
“This award is an honor, and validates that we have the expertise necessary to pursue a much larger scale of biomedical research in the future,” he said, noting UD’s new Institute for Engineering Driven Health announced in late 2021.
Emily Day, with the Department of Biomedical Engineering, joined UD in 2013 after completing her doctorate in bioengineering at Rice University and a postdoctoral fellowship in chemistry at Northwestern University. Her lab at UD develops innovative nanomaterials that enable high precision therapy of cancer, blood disorders and other diseases while also studying nanoparticle interactions with biological systems from the subcellular-level to a whole-organism perspective. Day also has been recognized with an NSF CAREER Award along with dozens of other awards and grant honors.
The general idea of her work, Day said, is to “make carriers that can get therapeutic cargo where it needs to go in the body in a more precise and more effective way.”
Day said she is honored to be an AIMBE Fellow and excited by the advocacy opportunities the organization provides, as it will enable her to be a voice for science-supported policies promoting biomedical research that can ultimately improve patient care.
“Being a Fellow of AIMBE is not just an honor, but also a responsibility,” Day said. “The election of four UD faculty members this year demonstrates that the type of research being done in our College is top-quality science worthy of national recognition and that our faculty members are true advocates for the advancement of biomedical research.”
Darrin Pochan, who leads the Department of Materials Science and Engineering, joined the UD faculty in 1999 as one of the first members of the then-new Department of Materials Science and Engineering. He has published over 150 peer-reviewed articles with more than 22,000 citations and was named chair in 2014. Among other accolades, he is a Fellow of the American Physical Society, American Chemical Society and the Royal Society of Chemistry in the United Kingdom.
His research team uses tools from biology, such as biomolecules like peptides, to harness their complexities for the creation of future biomedical materials and sustainable materials. His highly collaborative pursuits, which he said rely on close partnerships with computational, chemistry and biology experts, ultimately aim to address the world’s grandest challenges, from having organs available for transplants to biodegradable polymer materials.
“It’s an honor to be recognized by institutions such as the AIMBE that are quite interdisciplinary,” Pochan said. “At UD, we attract world experts in these fields, and fellowships in these societies recognize this leadership. This really highlights the exciting, interdisciplinary nature of the world-class research we do at the University of Delaware.”
Liyun Wang, a biomechanics expert in the Department of Mechanical Engineering, joined the faculty at UD in 2005 following postdoctoral research in orthopedics at Mount Sinai School of Medicine. She serves as director for UD’s Center for Biomechanical Engineering Research and co-director of the Multiscale Assessment Research Core in UD’s new Delaware Center for Musculoskeletal Research. She also is a member of several notable professional organizations, including the American Society of Bone and Mineral Research, the Biomedical Engineering Society and the Orthopedic Researchers Society.
Wang’s research has focused on how mechanical forces affect body functions, particularly for patients who may be suffering from other health conditions such as osteoporosis, osteoarthritis or cancer — or the new realm of “mechanobiology,” she explained. Wang said it was the collaborations not only in her lab, but across the College and University that have helped propel her cross-disciplinary work in musculoskeletal research to earn the recognition of groups like the AIMBE.
“Our ultimate goal is to amplify and increase the efficiency and safety of exercise on both healthy people and patient populations,” Wang said. “This honor is a recognition of all the hard work done by my former and current students and postdocs, as well as my collaborators.”
These four fellows join 13 other University of Delaware faculty members (past and current) that have been named AIMBE Fellows. Past honorees include E. Terry Papoutsakis (Class of Fellows 1993), Abraham M. Lenhoff (2003), David C. Martin (2005), Kelvin Lee (2010), Kristi Kiick (2012), Dawn M. Elliott (2013), Randall L. Duncan (2017), Millicent Sullivan (2017), Jill Higginson (2019), LaShanda Korley (2020) and Thomas Epps (2021).
Article by Maddy Lauria | Photo illustration by Joy Smoker
UD’s Charles Dhong gets $1.9 million to develop new tactile aids
Bumps and lines make up touch-based technology such as Braille. But the human sense of touch is keen enough to detect differences that are much smaller. Research by Charles Dhong and his group at the University of Delaware has found that humans can feel differences in the chemical composition of a surface, down to the substitution of a single atom.
That ability is one focus of Dhong’s work as an assistant professor in the Department of Materials Science and Engineering and the Department of Biomedical Engineering at UD. He explores new possibilities for tactile technologies and the mechanical forces that affect the perception of touch.
Dhong presented research on this at the American Chemical Society’s national meeting in San Diego on Wednesday, March 23. And he and collaborator Jared Medina, associate professor in UD’s Department of Psychological and Brain Sciences, have new support for development of higher-quality tactile aids for people with visual impairments. The $1.9 million grant, which started in February and continues for five years, is from the National Eye Institute in collaboration with the National Federation of the Blind.
Current technology recreates tactile sense using tiny motors and electricity. But the bumps and buzzes they generate are not that good at mimicking the real thing.
A new approach to controlling perception of texture could have many applications, Dhong said. It could make it possible to design new types of surfaces or provide improved integration of the sense of touch into virtual reality environments. It could also improve existing devices, such as Braille displays, or provide feedback to surgeons conducting surgery remotely.
“When you touch an object, you’re feeling its surface, and you can change how it feels by changing the friction between that surface and your finger. That’s where the chemistry comes in,” Dhong said. “We think materials chemistry could open the door to recreating more nuanced sensations, whether you’re designing a product to feel a certain way or creating feedback devices for virtual reality.”
Research by Charles Dhong and his group at the University of Delaware has shown that humans can feel tiny differences in a surface, down to the substitution of a single atom.
Progress in touch technology has lagged, in part because it involves multiple types of sensations, such as temperature and pain. In addition, some efforts to recreate touch have included systems designed to simulate a sense of moving one’s body — a complex sensation.
Dhong’s research focuses on a specific type of touch: using the fingers to detect fine textures. Some methods for evoking this kind of fine touch are already available. Your smartphone attracts your attention without sound, using a tiny vibrating device within. A refreshable Braille display for people with low vision or blindness uses an actuator to move pins up to create bumps.
This type of touch depends on a physical force — friction — which is the resistance that skin encounters as it brushes against an object. While attributes such as the contours of a surface influence friction, so does chemistry. The structure of the molecules within a substance and the properties of its surface also influence the sensation.
Dhong and his colleagues suspected that by altering only chemistry-related features, they could change how a surface feels.
In previous work, Dhong’s team asked people to touch single-molecule-thick layers of silane, a silicon-containing compound. None of the silane surfaces possessed detectable differences in smoothness.
But those who touched the surfaces could differentiate them based on chemical differences, including the substitution of one atom within each silane molecule for another, because of subtle changes in friction.
“Recent research has shown that people can detect the physical differences between surfaces at a resolution as low as 13 nanometers,” Dhong said. “Now we are saying that the sense of touch can also identify chemical changes as small as swapping a nitrogen atom for a carbon atom.”
In San Diego, Dhong presented recent work focusing on polymers, the go-to molecules for synthetic materials. Polymers are distinguished not only by their chemical formulas, but also by a characteristic known as crystallinity, which describes how neatly the chain-like molecules are organized. The polymers in these experiments had identical formulas and molecular weights. Only the degree of crystallinity differed.
In their experiments, the researchers focused on the perceived texture of thin layers of polymers. As with the silanes, they asked the subjects to slide their fingers across the polymer. This time, too, they found that people could differentiate between the polymers based only on variations in the friction resulting from subtle changes to the crystallinity of the molecules.
About the researcher
Charles Dhong, assistant professor of materials science and biomedical engineering in the College of Engineering, joined the University of Delaware faculty in 2019.
He earned his bachelor’s degree in chemical and biomolecular engineering at the University of California, Berkeley, his doctorate at Johns Hopkins University and did postdoctoral research in nanoengineering at the University of California, San Diego.
His research focuses on understanding the mechanical forces that shape the human sense of touch.
Article by UDaily staff, including content from the American Chemical Society Photo | illustration by Christian Derr, photo by Maria Errico, image of hand courtesy of Charles Dhong