Luminescent
materials produced by the MIT team are shown under ultraviolet light,
emitting different
colors of light that can be modified by their environmental conditions.
These
light-emitting beads were made by materials science and engineering
students Caroline
Liu and Rebecca Gallivan. Photo: Tara Fadenrecht
New family of luminescent materials could find broad uses in
chemical and biological detectors.
(September 4, 2015) Researchers
at MIT have developed a family of materials that can emit light of precisely
controlled colors — even pure white light — and whose output can be tuned to
respond to a wide variety of external conditions. The materials could find a
variety of uses in detecting chemical and biological compounds, or mechanical
and thermal conditions.
The material, a metallic polymer gel made using rare-earth
elements, is described in a paper in the Journal of the American Chemical
Society by assistant professor of materials science and engineering Niels
Holten-Andersen, postdoc Pangkuan Chen, and graduate students Qiaochu Li and
Scott Grindy.
The material, a light-emitting lanthanide metallogel, can be
chemically tuned to emit light in response to chemical, mechanical, or thermal
stimuli — potentially providing a visible output to indicate the presence of a
particular substance or condition.
The new material is an example of work with biologically
inspired materials, Holten-Andersen explains. “My niche is biomimetics — using
nature’s tricks to design bio-inspired polymers,” he says. There are an amazing
variety of “really funky” organisms in the oceans, he says, adding: “We’ve
barely scratched the surface of trying to understand how they’re put together,
from a chemical and mechanical standpoint.”
Luminescent
materials produced by the MIT team are shown under ultraviolet light,
emitting different
colors of light that can be modified by their environmental conditions.
These
light-emitting beads were made by materials science and engineering
students Caroline
Liu and Rebecca Gallivan. Photo: Tara Fadenrecht
Studying such natural materials, evolved over millions of
years to adapt to challenging environmental conditions, “allows us as engineers
to derive design principles” that can be applied to other kinds of materials,
he adds.
Holten-Andersen’s own research has examined a particular
kind of crosslinking in the threads mussels use to anchor themselves to rocks,
called metal-coordination bonds. These bonds, he adds, also play an important
role in many biological functions, such as binding oxygen to hemoglobin in red
blood cells.
He emphasizes that the idea is not to copy nature, but to
understand and apply some of the underlying principles of natural materials; in
some cases, these principles can be applied in materials that are simpler in
structure and easier to produce than their natural counterparts.