Phosphorescent material inspired by `glow in the dark' wood

Date:
August 23, 2021
Source:
University of Bath
Summary:
Scientists have harnessed the natural ability of wood to faintly
glow to develop a new sustainable phosphorescent material that could
potentially be used in a wide number of applications, from medical
imaging and optical sensing to 'glow in the dark' dyes and paints.



FULL STORY ========================================================================== Scientists have harnessed the natural ability of wood to faintly glow to develop a new sustainable phosphorescent material that could potentially
be used in a wide number of applications, from medical imaging and
optical sensing to 'glow in the dark' dyes and paints.


==========================================================================
An international team of researchers led by North East Forestry
University (China) and the University of Bath (UK) investigated the
natural phosphorescent properties of lignin, a major component of wood.

Room-temperature phosphorescence (RTP) is when a material absorbs energy
with a short wavelength (such as UV light) and then emits it as visible
light. This contrasts with fluorescent materials, which immediately emit
the light again and stop glowing when the light is switched off.

The researchers found that basswood naturally and weakly phosphoresces, releasing light for a few milliseconds due to lignin being trapped within
a 3D matrix of cellulose.

This inspired them to mimic the glowing properties by crosslinking lignin within a 3D polymer network, which caused it to glow visibly for around
one second.

They found by tweaking the cavity sizes within the network, and varying
drying times of the polymer, they could alter the duration of the
phosphoresce.



========================================================================== Professor Tony James, from the University of Bath's Centre for Sustainable Circular Technologies (UK), said: "All lignin glows weakly, but most of
the light energy is lost by vibration or movement of the lignin molecules, meaning it isn't clearly visible to the naked eye.

"We've found that immobilising the lignin in an acrylic polymer means more energy is emitted as light -- in other words, the less it rattles about,
the more it glows! "Most current phosphorescent materials are either
toxic or difficult to prepare, so we wanted to develop a new material
that overcame these limitations.

"Although there is room for improvement, our new material shows great
potential for making a more stable, sustainable, biodegradable non-toxic phosphorescent material that could be used in a range of applications."
To demonstrate the new material, the team used them to dye threads that
could be used in luminescent textiles. This has potential use for the
easy identification and the anti-counterfeiting protection of luxury
textiles or bags.

Lead corresponding author on the paper Professor Zhijun Chen, from the Engineering Research Center of Advanced Wooden Materials at Northeast
Forestry University (China), said: "It is indeed an unexpected and
interesting discovery.

"We think this work will not only provide a new option for sustainable afterglow materials but is also a new route for the value-added
utilisation of lignin, which is the main naturally occurring aromatic
polymer, and the pulping industry produces 600 trillion tons per year." ========================================================================== Story Source: Materials provided by University_of_Bath. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jingwen Yuan, Yingxiang Zhai, Keliang Wan, Shouxin Liu, Jian Li,
Shujun
Li, Zhijun Chen, Tony D. James. Sustainable afterglow materials
from lignin inspired by wood phosphorescence. Cell Reports Physical
Science, 2021; 100542 DOI: 10.1016/j.xcrp.2021.100542 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210823125815.htm

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