Chih-hung Chang: Nanotechnology on a T-shirt

Chih-hung Chang standing in front of an array of photovoltaic panels.
Chih-hung Chang, professor of chemical engineering, works with nanostructured thin films and printable electronics, with applications from solar panels to smart textiles.

In the near future, you might be able to charge your smartphone using solar panels printed directly onto your T-shirt, says Oregon State chemical engineering professor Chih-hung Chang.

Perhaps that same shirt will contain sensors that take your temperature or monitor your health by sampling your sweat. Or maybe the fabric will change color to alert you to environmental threats.

“I love coming up with new ideas,” Chang said. “It’s always exciting to try new things.”

Chang is optimistic about the potential for “smart textile” applications like these. An expert in printable electronics, Chang is currently working on a project supported by the Walmart Manufacturing Innovation Foundation that aims to print functional electronic devices directly onto fabrics.

“Right now we’re at the stage where we want to be able to fabricate components onto the fabric, including transistors or solar cells,” Chang said.

The way printable electronics are fabricated is similar to inkjet printing, Chang says. A silicon microfluidic chip dispenses microscopic droplets of different inks with a very high degree of accuracy. Only with this printer, instead of different colored pigment inks, molecular and nanoparticle “inks” function as conductors, semiconductors, and insulators.

“We are working to develop the inks that will be used to print electronics using print-additive techniques,” Chang said. “And we’re looking at energy-efficient curing processes, like microwaves, to make smart textiles.”

Printable electronics are just part of what Chang spends his days on. The majority of Chang’s work, largely funded by the National Science Foundation, focuses on using microchemical reactors in the creation of nanomaterials, nanostructures, and thin films.

“We use microreactors as a tool for manufacturing and also for fundamental study,” Chang said. “In the reactor, we generate all sorts of reactive species, including nanoparticles. We send these to a surface, and then they reorganize themselves on the surface to create nanostructured thin films.”

These thin films are used in a variety of applications, including photovoltaic cells, heat-transfer surfaces for electronic devices, and a variety of chemical sensors.

Some of Chang’s recent projects, supported by the Department of Energy’s National Energy Technology Laboratory, have potential applications in carbon sequestration. Chang’s work focused on using organic/inorganic hybrid nanomaterials to capture carbon dioxide, and also using nanomaterials to enhance near-infrared signals for monitoring carbon dioxide.

Chang’s own spinoff company, CSD Nano, developed a process to retrofit solar cells with a nanostructured coating that increases the output from existing solar farms. Chang founded the company in 2007. He currently advises the firm, sits on its board, and serves as its chief science officer.

Another Oregon company, Abom, turned to Chang to help develop its next-generation patented self-defogging ski goggles. Supported by ONAMI, Chang worked with his collaborator, Dr. Rajiv Malhotra, to develop innovative processes used in the defogging technology as well as a proprietary lens coating material.

Developing sustainable processes, by reducing energy consumption and achieving higher material utilization, is a guiding principle in Chang’s work. One major emphasis is developing a scalable manufacturing process for nanomaterials.

“The hope is that by making these processes more efficient, devices will be more cost-effective so they can be commercialized,” Chang said. “We want to get them into the market.”

Chang says he derives great personal satisfaction from his work, and working with students is one of the job’s major perks.

“It keeps your mind fresh, as you get older,” he says. “I think it’s very gratifying to see a student get excited about a project. Once they are motivated, they just do it themselves. In the research area, that’s the part that I like the most. To come up with new ideas and try them out in the lab and working with students.”

When he was himself a student, Chang says he was first drawn to study art, but he ultimately decided on chemical engineering. However, he doesn’t see the two as being mutually exclusive.

“I feel like I still get to do art,” he says. “Lots of people are using smart textiles for artistic expression in T-shirts. For example, you can have lighting or other interesting effects — for fashion, not necessarily for function. As engineers, of course, we care a lot more about function.”

Chang recently found creative inspiration in a collaboration with Sara Robinson, professor of wood science and engineering in College of Forestry. Their project, another Walmart-funded venture, aims to turn biopigments from fungi that grow on wood into printable inks for textiles.

“I actually bought a T-shirt printer, just to play around with,” Chang said. “My idea is that once I have the ink, I can design T-shirts and print them myself.”

CBEE seniors’ hard work, ingenuity on display

Student giving presentation of project.
CBEE students present senior projects at the 2017 Engineering Undergraduate Expo, outside Johnson Hall.

For students in the School of Chemical, Biological, and Environmental Engineering, the senior project represents the crowning achievement of years of determination, work, and study. It also provides those who are about to graduate an opportunity to demonstrate to their mentors, peers, and community just how much they’ve learned.

These projects — undertaken with the supervision of either a faculty mentor or one of the school’s industry partners — require students to tackle real-world challenges using their hard-earned engineering skills and creative problem-solving abilities.

Administered by Philip Harding, Linus Pauling Engineer, the CBEE senior projects are formulated in the fall and assigned in late January. Work begins in mid-February. A listing of this year’s senior projects is now online. (Check back throughout the spring term for links to the teams’ most recent presentations, along with projects from previous years.)

The senior projects culminate in the College of Engineering’s Engineering Undergraduate Expo and final presentations in mid-June.

Each year, the Expo offers an amazing breadth of engineering talent and ingenuity, featuring projects by seniors throughout the College of Engineering. The 2018 event will take place on Friday, May 18, in the Kelley Engineering Center, Johnson Hall and Community Plaza.

Industry experience: Making the right choice

Zachery Knudsen
Chemical engineering junior Zachery Knudsen says his internship experience confirmed for him that engineering is the right choice, and that industry is where he wants to be.

Zachery Knudsen jokes that he worked in just about every job you can have without going to college before he decided to pursue chemical engineering at Oregon State.

Never afraid of hard work, the 25-year-old junior from Las Vegas tried his hand at all kinds of jobs in construction, as a mechanic, even working in restaurants. But he had yet to find a job he wanted to make a career out of.

Last summer, Zach went to Longview, Washington, to work as an engineering intern at KapStone Paper and Packaging’s huge mill there. From the beginning, he says, his experience there confirmed that he had made the right career choice.

“During the first week, I shadowed one of the full-time engineers,” he said. “One of the dryers wasn’t working properly, and nobody could figure out why. This guy went out there, checked things out, got into the controls, changed a few things — and it started working again. I thought to myself: ‘This is exactly why I got into engineering, to solve problems.’”

In any production environment, there are always problems to be solved. KapStone’s Longview mill is huge, with a footprint of more than 100 acres and a capacity of 1.45 million tons per year. It’s also an older facility, operating on the same site since 1927. The problem Zach worked on isn’t very small or very new either: His work was part of the preparations for an overhaul to the mill’s white water system, a significant plant upgrade that the company has been planning for years.

Paper machine
One of the paper machines at KapStone Paper and Packaging’s mill in Longview, Washington. (Courtesy of KapStone)

On its way to becoming paper, wood pulp is laid out on wire supports that convey it through the mill. The pulp is sprayed with water from showers to keep it manageable and to help the fibers align properly. The wire itself is also sprayed to keep it clean and free of pulp residue. The used shower water, now an opaque waste product called “white water,” drips into a catch basin beneath the wire to be recycled.

Problems arise when pulp fibers suspended in recycled white water become trapped in shower nozzles, clogging them. This results in increased downtime for maintenance and, consequently, reduced production. Unchecked, it can lead to equipment failure and product losses. All of these are unrecoverable costs to the company. Zach’s work focused on two of the five machines running at the mill.

“I worked on understanding how all the water was fed, where the water was going, basically doing a big mass balance/energy balance around the whole machine,” Zach said. “They use WinGems modeling software, pretty much the standard in the pulp and paper industry. They had already built a model of what the white water system looked like. I just made improvements to it, like determining more precisely how much water was really in the system, determining the locations of all of the pumps, and just trying to get the numbers as close as possible to where the machines really are.”

Once that work was done, the team performed an economic analysis and determined that a whitewater filtration project could save the company about $800,000 per year, with a return on investment of 130-150 percent.

Zach says his summer experience gave him an opportunity to put some of his classroom learning to use in the real world.

“I used a lot of the ideas I learned in mass balances and energy balances, process dynamics, and problem solving in general. Eventually, I’ll take process controls, and I got a lot of hands-on exposure to that while I was there, too.”

Spending the summer at KapStone confirmed a few things for Zach. He says he now knows for certain that he wants to be in industry, that he wants to stay on the West Coast, and that he picked the right major.

“I saw what the full-time engineers were doing, and that looked like something I want to be doing,” he said. “After working so many jobs, this reassured me that this is exactly what I want to do.”



Industry experience: Putting MATLAB to work

Anthony Pyka
Anthony Pyka spent his summer working with MATLAB on a project with the Funai Corporation.

Persistence and stubbornness are the two qualities that Anthony Pyka says drew him to study chemical engineering at Oregon State. They’re also the qualities that served him well last summer, when he was working as an intern with the Funai Corporation. It was an experience that he says was as rewarding as it was challenging.

Anthony worked under the direction of Dr. Manish Giri, an Oregon State alumnus and 2017 inductee in the Council of Outstanding Early Career Engineers. Their project involved building on Funai’s microfluidics technology to create an accurate and portable liquid handling platform.

The underlying technology — using a silicon microfluidic chip to dispense picoliter-scale quantities of liquids with a high degree of accuracy — is familiar to anyone who has seen an inkjet printer in operation. But this technology shows great promise for a wide variety of applications, not just in industrial and consumer printing, but also in biomedical pico-dispensing, and microfluidic modules for lab-on-chip and point-of-care devices as well.

Anthony’s part of the project involved integrating an image validation system. He was given a computer and a USB camera to work with. He chose MATLAB as the scripting language because of its convenient image-processing software packages.

“I thought I knew a lot of MATLAB after being an undergraduate teaching assistant for CBEE’s freshman coding class,” Anthony said. “I was completely wrong. This internship showed me how different components of MATLAB can come together to complete a goal.”

Anthony learned different logging techniques and organizing functions to complete image processing. He says these skills helped his understanding of matrixes and made him more familiar with scripting languages, both important to industry and his own education. As with any learning process, it wasn’t always fun.

“At first it was frustrating to see ‘ERROR’ pop up every time I tried to run a code,” Anthony said. “I would often leave work with my code not working, only to come back again the next day and try something different.”

Eventually, everything worked. After six weeks and 600 lines of code, Anthony had a working system that could scan a print job accurately and send processed data to an executable user interface, so users could examine photos and determine whether a sample was printed to proper specifications.

“In class I had to use MATLAB as a modeling program and as a calculator,” Anthony said. “It was exciting to use MATALB for a practical application. “Maybe now I can build and control something on my own!”

Developing technologies for a clean-energy future: Zhenxing Feng

Zhenxing Feng supervises students in his laboratory.

Zhenxing Feng’s research focuses on the chemical processes involved in energy storage and conversion. Specifically, he is interested in developing and improving devices — such as batteries and fuel cells — instrumental in effecting the world’s transition to clean, sustainable, and renewable energy.

An assistant professor in chemical engineering, Feng came to Oregon State in the fall of 2016 after spending three years as a researcher at the Joint Center for Energy Storage Research at Argonne National Laboratory. Feng says his science background enables him to have a solid grasp of chemistry at the atomic level, but he derives great satisfaction from applying this knowledge to real-world problems on a human scale.

“I started off studying physics, but I really wanted to see applications,” Feng said. “All the work I am doing has the potential to make changes in everyday life. For example, battery technology has become a hot topic lately because of electric cars. This is an area where small details can create a big impact.”

If you want to build a better battery, Feng says, you first need to understand how it works. A big part of Feng’s work focuses on fundamental studies for elaborating the processes at work in existing technologies to identify potential inefficiencies and areas for improvement.

“We try to do things rationally,” Feng says. “If we know, for example, that a cathode is the bottleneck for the development of next-generation battery, we will identify factors that can improve the cathode performance. The best way to diagnose the device is to ‘see’ what is going on inside it during its operation, which is called in situ operando studies.”

These studies often involve trips to national facilities, such as the Advanced Photon Source at Argonne National Laboratory and Advanced Light source at Lawrence Berkeley National Laboratory, where high-flux and bright X-rays are generated to penetrate the working devices (e.g., battery and fuel cells) in a non-destructive way but provide atomic structure and chemical information of materials that researchers are interested in.

“It is like a doctor using a CT scan to examine a patient,” said Feng.

One of Feng’s projects is focused on the development of safe, high-energy-density, lithium-ion batteries with long cycle life for applications both in small electronic devices, such as laptop computers, and in electric cars.

The state-of-the-art lithium ion batteries in today’s electric cars can support a range of only around 100 miles, one-third the range of a typical gasoline-powered car. By using a lithium-conducting thin layer to coat the surface of the battery’s cathode, Feng has improved the energy density more than 30 percent, as the modified cathode can be operated at higher voltage. Furthermore, this improvement elongates the cycle life about two to three times longer than commercial lithium-ion batteries, due to the robust surface protection.

Feng’s research is also looking beyond lithium-ion technologies, including lithium-sulfur batteries, which offer eight times the storage density of current lithium-ion batteries, and solid-state batteries, which eliminate the need for liquid electrolytes and can work under extreme high or low temperatures.

“This could be useful if we want to go to Mars, for example,” Feng said. “However, these advanced technologies have problems in stability and cycle life that will need to be overcome before they can be considered a practical alternative”

In the area of energy conversion, Feng is examining the possibility of using low-cost metal oxides as catalysts in fuel cells to replace precious metals like platinum. A fuel cell is a clean-energy device that uses zero-pollution fuels, hydrogen and oxygen, to generate electricity. Their low efficiency is the key issue that prevents their wide commercialization, and a cost-effective catalyst could be their salvation. Feng is also interested in using catalysts to convert carbon dioxide into useful fuels, which is called the carbon-neutral process.

Feng’s work has received funding support from the Joint Center for Energy Storage Research and the Energy Frontier Research Center of the U.S. Department of Energy. He is the current Callahan Faculty Scholar in Chemical Engineering at Oregon State. In 2017, he was named a Scialog Fellow of Research Corporation for Science Advancement, which recently awarded him a grant for his advanced energy storage research.