Research Spotlights

Improving energy materials by understanding heat flow on the atomic scale

By Georgia Barrington-Smith & Dr Rebecca Duncan

With advancements in technology and increases in population leading to a looming energy crisis, it is vital to optimise energy use to meet our future needs. One of the major issues in energy generation is the production of wasted energy in the form of heat. To address this issue of heat loss, we need efficient materials that harness this thermal energy to be used in industries and homes. This practise will enable more efficient energy generation and thereby reduce carbon emissions.

Investigating heat flow in materials

To gain the insights necessary to develop these new materials Caleb Stamper, an AINSE PGRA student, and his collaborators at ANSTO and the University of Wollongong, have investigated the mechanical vibrations of atoms that are responsible for the transport of heat in materials.

Using inelastic neutron scattering techniques combined with structural and thermal property measurements, Caleb was able to explore how heat flows through materials at the atomic scale. Of particular interest to the team were thermoelectric materials, which enable the direct conversion of heat back in to useful electrical energy.

Exploring energy efficient materials

One important consideration for designing heat efficient materials is how well a material retains heat. Materials with low thermal conductivity are ideal, since heat travels slower across such materials, thereby helping them retain heat for longer before expelling it as wasted energy.

Caleb and his collaborators projected that thermoelectric materials could be made more efficient with the addition of carbon nanoparticles, which might significantly lower the material’s heat conductivity. To understand this process, Caleb conducted experiments to investigate the atomic vibrations of pure thermoelectric materials, pure nano-carbon materials, and composite variations. He was able to show that carbon nanocomposites significantly reduce heat conduction, thereby improving the performance of thermoelectric materials.

Exploring energy efficient liquids

As well as investigating solids, the team were also interested in understanding heat transportation in liquids. This poses unique challenges due to liquids having an inherently disordered nature on the atomic scale.

Previously a team of European and Chinese scientists had proposed a theory that could predict the shape of the vibrational density of diverse states of liquids, ranging from hydrogen-bonding small molecular liquids (such as water), liquid metals (such as gallium), and larger, more viscous molecular liquids.

Employing inelastic neutron scattering techniques at ANSTO’s Australian Centre for Neutron Scattering (ACNS), Caleb and his collaborators were able to experimentally confirm this theory, thereby unlocking new information about the thermal properties of complex materials like nanoparticle composites and liquids. These findings will assist in engineering new, more efficient thermal materials that can meet increasing global energy demands.

If you want to be a part of solving the challenges of Australia’s future energy needs, like Caleb, visit ainse.edu.au/scholarships to see how AINSE can support you.

AINSE are proud to spotlight the impressive work of supported students like Caleb.

Read more research spotlights at ainse.edu.au/research-spotlights, and keep an eye out for our December edition, where, in the spirit of the festive season, we will be looking at research done in our polar regions. First off the sled is Dr Rebecca Duncan, who journeys to Santa’s north pole to investigate the effects of climate change on the polar marine food web.

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By Georgia Barrington-Smith & Dr Rebecca Duncan

Cancer continues to be one of the leading causes of death worldwide, claiming the lives of millions of people each year. One of the first-line treatments of cancer is chemotherapy: powerful drugs that attack cancer cells and prevent their spread.

Historically, the main drawback of chemotherapy drugs has been their non-specific nature, meaning they attack both cancer cells and healthy cells indiscriminately. As a result, these drugs can have many adverse side-effects impacting a patient’s quality of life. To negate these effects, new chemotherapy pharmaceuticals are under development that use drug carriers called nanoparticles.

Precise delivery of chemotherapy drugs

Nanoparticles act like special couriers that carry necessary chemotherapy drugs around the body delivering them directly to the site of the tumour without stopping at healthy tissue.

Several types of nanoparticles have been explored for cancer treatments including polymeric micelles (PMs). Current work in this area is looking at developing PMs that can respond to environmental changes inside the cells, such as pH level. Once at the site of the tumour, which is often more acidic than healthy cells, the PMs sense the pH change. This triggers them to disassemble and release the chemotherapy drugs, effectively killing the cancer cells from the inside out. As well as being useful drug carry cases, PMs have a range of other benefits including improved solubility, prolonged circulation, and reduced toxicity.

Exploring the properties of nanoparticles

Cintya and her collaborators observed the PM disassembly process using dynamic light scattering techniques at ANSTO’s Australian Synchrotron. By performing small-angle X-ray scattering (SAXS) experiments using the SAXS/WAXS beamline, the team showed that the PMs remained intact in non-acidic conditions and completely disassembled in acidic environments. Their experiments also revealed that small changes to PM chemical structure had significant impacts on their size and shape. This is important because size, shape, and surface features of PMs can drastically alter how they behave in biological systems.

As more nanoparticles enter clinical use, it is imperative that we understand how their structure influences their properties. Cintya’s research added valuable insights into how the pH-responsive behaviour and shape of PMs can be tuned, based on subtle changes in their chemical structure. These outcomes will greatly aid researchers in designing the next generation of life-saving cancer treatments.  

Cintya’s research journey with AINSE and ANSTO

Cintya recalls her PGRA experience as “such an amazing opportunity” that she was incredibly “grateful for the support” offered by AINSE. Having access to ANSTO’s Australian Synchrotron meant she was able to gather “valuable data” for her thesis and be a part of a “supportive ANSTO community”. She recalls how “invaluable the beamline scientists” were, making the experience incredibly rewarding.

We at AINSE are proud to spotlight Cintya for her ground-breaking work!
She has made an important contribution by using nuclear science and technology to improve cancer treatments.

Cintya has left the world of research to pursue a career in science communication at Scientell, helping others share their amazing science with the world.
Congratulations Cintya!

Keep up to date with our regular content and monthly research spotlights, including research from Caleb Stamper later this month, who is working on ‘improving energy materials by understanding heat flow on the atomic scale’.