Materials scientist Marilyn Rampersad Mackiewicz has developed a new method for precisely shaping silver nanoparticles using ultraviolet light—a breakthrough that could dramatically improve the performance and durability of these nanoscale workhorses in fields ranging from medicine to electronics.
Her research team also discovered how to stabilize the nanoparticles in the presence of light and oxygen—two elements that typically degrade them—offering a powerful one-two solution to challenges that have long limited their use.
“This breakthrough could truly revolutionize the field,” said Oregon State materials scientist Marilyn Rampersad Mackiewicz, who led the study.
Nanoparticles are pieces of material ranging in size from one- to 100-billionths of a meter. Silver nanoparticles are incorporated into products including sanitizers, odor-resistant clothes, washing machines, makeup, food packaging and sports equipment. They are able to kill microorganisms and are industrially important as catalysts.
The research by Mackiewicz, associate professor of chemistry in the OSU College of Science, sought to overcome a pair of enduring challenges in the silver nanoparticle field: How to easily make them in uniform shapes and sizes, and how to keep them from degrading.
“Having silver nanoparticles of the same shape and size ensures they work effectively and reliably, making them more useful and efficient,” Mackiewicz said. “And the longer they can maintain that size and shape, the more valuable they are.”
When silver nanoparticles are uniform, they display consistent physical and chemical properties, including optical, electrical and catalytic behaviors. Uniformity is vital to applications that rely on precise interactions at the nanoscale, including the nanoparticles’ use:
- In wound dressings, coatings for medical devices and drug delivery systems.
- As conductive inks and other components of printed electronics.
- In water purification systems as a means of removing harmful microorganisms.
- In sensors and imaging devices used in medical diagnostics and environmental monitoring.
In this study, Mackiewicz, research assistant Citlali Nieves Lira and doctoral student Hao Yue uncovered a comparatively quick and simple way to use ultraviolet light, coupled with oxygen and positively charged silver ions, to convert different shapes of nanoparticles into triangular ones of identical size.
“Our study provides a deeper understanding of the roles that light, silver ions and oxygen play in the shape transformation process for silver nanoparticles,” Mackiewicz said. “What we learned will aid in the design of better synthesis methods, improve the performance of silver nanoparticles and ultimately make the world both safer and more efficient.”
The National Science Foundation supported the research, which was published in the Journal of Physical Chemistry.
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