A team of Florida State University researchers has discovered a way to use energy-efficient light to manipulate photopolymers or plastic films — a finding that has implications for a wide variety of technologies that use light as an energy source to create shape-shifting structures.
The research is published in the journal ACS applied polymer materials and is a joint work of Associate Professors of Chemistry and Biochemistry Ken Hanson and Justin Kennemur, and FAMU-FSU College of Engineering Professor William Oates.
“The idea is that we want to harness energy-efficient light and produce mechanical power as efficiently as possible,” Hanson said.
Researchers worldwide are working on materials that respond to external stimuli such as light, temperature, magnetic fields or electricity. These stimuli can cause a material to change shape, molecular arrangement or mechanical properties and have been used in research in robotics, aerospace engineering, drug delivery and more.
The research team at FSU was particularly interested in light-responsive systems for mechanical work, a less studied area.
So far, research in that area has shown that the conversion of light for this purpose is often energetically inefficient and requires high-energy light for significant results. Hanson, Kennemur and Oates believed that their combined expertise – Hanson is an expert in solar cells, Kennemur in polymer synthesis and Oates in materials characterization and modeling – could help them develop a new approach.
Their research team eventually collaborated on a new process that effectively harvests energy-efficient light and uses it to bend plastic films across the thickness of masking tape.
“Many polymers have stability limitations that result in slow degradation when exposed to high-energy ultraviolet light,” Kennemur said. “Using lower energy visible light is a great way to get around this problem.”
The FSU team experimented with a photopolymer based on the chemical compound stilbene. Stilbene itself has limited uses, but it can be used to make dyes, optical brighteners, or dye lasers. Hanson, Kennemur and Oates applied a mechanism called a triplet sensitizer to the polymer, which allowed it to absorb the low-energy light and convert it into high-energy mechanical work.
When the research team shone a dim light on the stilbene-based plastic filmsthey saw the films bend in response to the energy transfer.
“It’s remarkable how, for the first time, low-energy photons can manipulate stilbene to precisely control the shape of a polymer with polarized light,” Oates said.
Given this proof of concept, the researchers plan to further refine this process in the future using different polymer structures, light-absorbing nanostructures and advanced modeling tools.
Other contributors to this article are FSU students Drake Beery, Eugenia Stanisauskis, Grace McLeod, Gina Guillory, and postdoctoral researcher Anjan Das.
Drake Beery et al, Enabling lower energy light harvesting in stilbene-based photomechanical polymers via triplet sensitization, ACS applied polymer materials (2022). DOI: 10.1021/acsapm.2c00660
Florida State University
Quote: Shine a light: New research shows how energy-efficient light can bend plastic (2022, June 28) retrieved June 28, 2022 from https://phys.org/news/2022-06-low-energy-plastic.html
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