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Researchers use nanocellulose to create materials with new properties



From nanocellulose to gold

Nanocellulose decorated with metal nanoparticles. Credit: Magnus Johansson

When nanocellulose is combined with different types of metal nanoparticles, materials are formed with many new and attractive properties. They can be antibacterial, change color under pressure or convert light into heat.

“Simply put, we make gold from nanocellulose,”

; says Daniel Aili, associate professor in the Department of Biophysics and Bioengineering in the Department of Physics, Chemistry and Biology at Linköping University.

The research team, led by Daniel Aili, used a biosynthetic nanocellulose produced by bacteria and originally developed for wound care. The scientists then decorated the cellulose with metallic nanoparticles, mostly silver and gold. The particles, no larger than a few billion meters, are first adapted to give them the desired properties, and then combined with nanocellulose.

“Nanocellulose is made up of thin cellulose fibers, about one-thousandth the diameter of a human hair. The fibers act as a three-dimensional scaffold for metal particles. When particles join cellulose, a material that network of particles and forms of cellulose, “explains Daniel Aili.

Researchers can determine with high accuracy how many particles will be attached, and their identity. They can also be mixed with particles of different metals and with different shapes – spherical, elliptical and triangular.

From nanocellulose to gold

As the pressure increases, the material eventually appears to be gold. Credit: Magnus Johansson

In the first part of a scientific article published in Advanced functional materials, the group describes the process and explains why it works the way it works. The second part focuses on several areas of application.

An exciting phenomenon is the way in which the properties of the material change when pressure is applied. Optical phenomena arise when particles approach each other and interact, and the material changes color. As the pressure increases, the material eventually appears to be gold.

“We saw that the material changed color when we got it in the tweezers, and at first we could not understand why,” says Daniel Aili.

Scientists have described the phenomenon as “mechanoplasmic effect”, and it has turned out to be very useful. A closely related application is on sensors, as it is possible to read the sensor with the naked eye. An example: If a protein sticks to a material, it no longer changes color when pressed. If the protein is a marker for a particular disease, failure to change color can be used in diagnosis. If the material changes color, marker protein is not present.

Another interesting phenomenon is manifested by a variant of the material that absorbs light from a visible light with a much wider spectrum and generates heat. This property can be used for both energy-based and medical applications.

“Our method enables the production of nanocellulose composites and metal nanoparticles that are soft and biocompatible materials for optical, catalytic, electrical and biomedical applications. Since the material is self-assembling, we can produce complex materials with well-defined properties , “Daniel Aili concludes.


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More information:
Olof Eskilson et al. Self-determination of bacteriophage melanoplasmic cellulose-metal nanopermic composites, Advanced functional materials (2020). DOI: 10.1002 / adfm.202004766

Provided by Linköping University



citation: Researchers use nanocellulose to create materials with new properties (2020, August 10) Retrieved August 11, 2020 from https://phys.org/news/2020-08-nanocellulose-materials-properties.html

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