- The sensors operate through a previously unexplored mechanism that links nanoscale shape memory effects with visible color changes.
- Unlike most existing sensors, they require no power source and can provide immediate visual feedback.
- The technology shows promise for detecting chemicals in challenging environments such as solid materials and vapors – areas where conventional colorimetric sensors have been less successful.
The public encounters potentially harmful chemicals every day. The culprits can range from household items, indoor air quality, items in work settings or even transportation systems.
Home lead or asbestos test kits are available but not always reliable. But thanks to new research at the University of Florida, the availability of user-friendly, non-mechanical, reusable and affordable indicators may be on the horizon that will expose a wider variety of hazards.
Peng Jiang, Ph.D., a professor in UF’s Department of Chemical Engineering, or ChE, recently received a three-year National Science Foundation research grant that will help develop a new generation of non-mechanical, low-cost, reusable “smart” sensors that will visually detect hazardous chemicals by changing colors.
“If successful, this research could establish an entirely new platform for producing practical, color-changing chemical sensors that are inexpensive, reusable, easy to use and suitable for large-scale production,” Jiang said.
As an analogy, think of traditional pH paper that changes color when it encounters acids or bases. This new sensor will work similarly by changing color when exposed to a target chemical.
These sensors will allow immediate feedback without requiring power supplies, sophisticated laboratory equipment or advanced technical training to utilize the sensors.
“Our research seeks to place chemical sensing capabilities directly into the hands of users through simple visual indicators. For example, we are developing sensors that can detect toxic plasticizers in consumer plastics and hazardous vapors in the environment,” Jiang explained.
The need is there, according to several studies. A 2021 study in Nature Communications, for one, surveyed industrial, medical and environmental sectors and concluded that “most current chemo-sensing devices remain cost prohibitive and require specialist training.”
The broader significance of Jiang’s work is that hazardous detection could become more accessible, affordable and deployable in everyday environments.
“Such technologies,” he said, “could improve public health, strengthen environmental protection, support advanced manufacturing and create new opportunities for technology commercialization and economic growth.”
Over the past 10 years, Jiang’s research group built the foundation for this grant with the discovery of a new class of shape memory polymers (plastic materials that can return to their original shape with an external stimulus like heat, light or electricity).
“We discovered a new class of multi-stimuli-responsive shape memory polymers that exhibit unusual room-temperature shape memory behavior. Unlike conventional shape-memory materials that typically require heating, our materials can respond to mechanical forces and chemical stimuli under ambient conditions,” Jiang explained.
By combining those materials with bioinspired structural colors triggered by light, they can produce highly visible color changes in response to specific chemicals. Jiang’s group was able to detect trace amounts of ethanol, for example, using proof-of-concept sensors.
Their work also builds upon multiple patented technologies developed at UF.
“The technology shows promise for detecting chemicals in challenging environments such as solid materials and vapors, areas where conventional colorimetric sensors have been much less successful,” he added.
During the research, Jiang’s students will be exposed to advanced manufacturing, nanotechnology, materials science, sensors, modeling and entrepreneurship. Additionally, the project includes a K-12 outreach and curriculum to inspire younger students and spark interest in STEM fields.