Tag Archives: nanomaterials research

Drops from thin air

The University of Sydney Nano Institute team

University science is behind some of the most profound innovations and breakthroughs in water research, from the development of cutting-edge techniques to maximise irrigation, to the creation of innovative new materials that can literally capture water from the air.

At the University of Sydney, the Advanced Capture of Water from the Atmosphere (ACWA) project applies nanoscale materials science to mimic the remarkable adaptation of desert beetles in Namibia, a region where just 1.4cm of rain falls each year. The beetle collects water vapour from the atmosphere, turning it into liquid via the intricate shapes of tiny bumps on its exoskeleton.

Biomimicry — learning from, and mimicking, clever strategies found in nature to solve human design challenges — is an important component of the work of the University of Sydney Nano Institute, co-led by chemist Professor Chiara Neto and physicist Professor Martijn de Sterke. Innovations from the research include a nanotextured surface which can repel bacteria, algae and other marine life from ships’ hulls, inspired by a lotus leaf; a nanoscale slippery surface, inspired by the pitcher plant, that can be used for microfluidic channels in bioengineering; and a stain-resistant paint base.

The Institute has attracted top-level researchers from chemistry, physics, materials science and bioengineering from across the university.

“We began with the idea of capturing water from the atmosphere by optimising the surface chemistry of a material so it would enable the formation of droplets out of humid air,” says Neto.

“We are now developing new devices that capture water from the atmosphere through condensation, using no external source of energy, by designing surfaces that spontaneously cool when exposed to the air,” she says.

Related: Software saves rainwater

The team has made two key breakthroughs. First, they have perfected the surface science of nanoscale ‘bumps’ shaped in a way to harvest a very thin film of water vapour, similar to the Namibian desert beetle.

Their second breakthrough is the development of an entirely new surface that is naturally chilled and causes water to condense into droplets. Wherever the atmosphere is above 30% humidity, this surface will automatically collect water vapour from the air.

The ACWA project is well on the way towards its ambitious goal to create materials that capture sufficient water from the atmosphere to alleviate the effect of drought by providing water for humans, animals and plants.

Patents are underway for exciting applications for the technology, including watering devices to use within greenhouses; a portable self-filling water bottle for bushwalkers and emergency crews; and small water stations to sustain wildlife in remote areas

Fran Molloy

This article appears in Australian University Science issue 2.

aerogel

Turning jeans into joints: artificial cartilage from denim aerogel

This aerogel, which is synthesised from recycled denim, shares the material properties of joint cartilage. Image credit: Deakin University.

The team, which includes Deakin scientist Dr Nolene Byrne and PhD candidate Beini Zeng, have been pioneering advanced textile recycling methods in a joint project with Deakin’s Institute for Frontier Materials (IFM) and the School of Engineering.

One of their developments has been the use of recycled textiles to form aerogels.  Aerogels are a class of low density materials with a range of applications, which include water filtration and separators in advanced battery technologies.

Denim is an excellent candidate for forming aerogels because the cotton it is woven from is composed of a natural polymer, cellulose. “Cellulose is a versatile renewable material, so we can use liquid solvents on waste denim to allow it to be dissolved and regenerated into an aerogel,” explains Dr Byrne. The process is known as sol gel synthesis.

Aerogels have highly porous structures and extremely low densities. Dr Byrne describes the synthesis of the artificial cartilage aerogel as an unexpected discovery. “It has a unique porous structure and nanoscopic tunnels running through the sample. That’s exactly what cartilage looks like,” she said.

This surprising finding is particularly exciting because of the challenges involved with trying to control the properties of artificial cartilage in tissue engineering. “You can’t 3D print that material,” says Dr Byrne. “Now we can shape and tune the aerogel to manipulate the size and distribution of the tunnels to make the ideal shape.” The pores of the aerogel can be manipulated based on the drying technique – for example, supercritical CO2 drying is used to obtain an aerogel in the form of nanospheres.

The aerogels are now being tested to optimise their mechanical properties. “We are now entering pilot-scale trials and look to be at commercial scale within 3 to 5 years with industry support.”

This unique method of recycling denim will also help contribute to minimising textile waste, says Dr Byrne. “Textile waste is a global challenge with significant environmental implications, and we’ve been working for more than four years to address this problem with a viable textile recycling solution,” she said.

Textile recycling involves the use of chemicals, which can be both expensive and environmentally unfriendly. “We use environmentally-friendly chemicals, and by upcycling our approach to create a more advanced material we can address the limitations affecting other less cost-effective methods,” says Dr Byrne.

For more information, visit the Deakin Institute for Frontier Materials and the ARC Research Hub for Future Fibres.

– Larissa Fedunik

gemstones-nanomaterials

Tiny gemstones advance nanoscale imaging

Featured image above: Nanomaterials composed of tiny diamonds and rubies can be used to light up and image a long chain of proteins. Credit: Carlo Bradac

A research team at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) – led by Dr Philipp Reineck from RMIT University’s School of Science – tested the ruby and diamond particles, more than a thousand times smaller than the diameter of a hair, alongside other nanoparticles for use in biological imaging, and found that they have a higher degree of stability, critical to achieving imaging success.

“Fluorescing nanoparticles can be used as ‘tiny lamps’ that when placed in the body, are able to light up cells and their internal processes.”

“We shine light at the biological sample of interest in a very controlled way and the nanomaterials send light back, helping us to see very specifically what is happening, right down to a molecule and protein level.”

“This is the area we’re focused on, exploring how the ‘very small’ can help us in answering some of the very big questions in biology.”

In the study published in the journal Advanced Optical Materials, the team compared seven types of fluorescent nanomaterials – organic dyes, semiconductor quantum dots, fluorescent beads, carbon dots and gold nanoclusters, as well as the nano sized diamonds and rubies.

Characteristics tested for included levels of fluorescence brightness and photostability (resistance to change under the influence of light), as well as how efficiently these new materials can be imaged using standard microscopes used in biology.

“Nanomaterials have widely differing characteristics and we need to determine which materials will work best in which imaging application,” Reineck said.

“What our study clearly shows is that nanodiamonds and nanorubies are excellent materials for long-term biological imaging.

“These two materials provide acceptable levels of brightness and the best photostability by far, when compared to the other materials that were tested.”

In other study findings, Reineck noted clear trade-offs in many of the nanomaterials examined.

“We found that ideal levels of photostability generally mean a sacrifice in brightness and vice versa,” he said.

“For example, during testing, the organic dyes and carbon dots were much brighter than the rubies and the diamonds – but photobleaching (or fading) was a major issue, impacting their practical imaging use.”

Reineck’s next step will be to work closely with biologists and medical researchers within the CNBP to develop selected nanomaterials so that they can be used with the needed precision and reliability to light-up real-world biological environments.

Future application of the materials will relate to fertility, chronic pain and heart disease research, key focus areas for the CNBP.

“The real treasure isn’t the rubies or the diamonds,” concluded Reineck.

“It will be the way in which we use these materials to shed new light on the incredibly complex processes taking place in the living body, helping us understand a whole host of matters relating to health, wellbeing and disease.”

The Centre for Nanoscale BioPhotonics (CNBP) is an Australian Research Council Centre of Excellence, with research focussed nodes at the University of Adelaide, Macquarie University and RMIT University.

A $40 million initiative, the CNBP is focused on developing new light-based imaging and sensing tools, that can measure the inner workings of cells, in the living body.

– Petra van Nieuwenhoven

This article was first published by RMIT University on 20 July 2016. Read the original article here.