Breakthrough Solutions Top 5 Innovative Materials from 2022
Researchers across the globe have developed numerous breakthrough materials and are also making use of basic materials innovatively to produce highly efficient solutions. Lab Worldwide reviews the ‘Top 5 Innovative Materials’ from the year 2022.
New ‘Supramolecular Plastic’ is Degradable and Recyclable
Researchers have created a new eco-friendly ‘supramolecular plastic’ which has the potential to replace conventional plastic. The new material is easily degradable and highly recyclable in nature unlike its counterpart.
The Jianwei Li research group at the University of Turku, Finland, has discovered that a physical concept called liquid-liquid phase separation (LLPS) could sequester and concentrate solutes, strengthening the bonding force between molecules and driving the formation of macroscopic materials. The mechanical property of the resulting material was comparable with conventional polymers.
Moreover, once the material was broken into pieces, the fragments could be reunited and self-healed instantly. In addition, the material was an adhesive when saturated amounts of water were encapsulated. For example, the joint specimens made of steel could hold a 16 kg weight for over a month.
Finally, thanks to the dynamic and reversible nature of the non-covalent interactions, the material was degradable and highly recyclable.
“Comparable with conventional plastics, our new supramolecular plastics are smarter as they not only retain the strong mechanical property but also reserve dynamic and reversible properties that made the material self-healable and reusable,” explains Postdoctoral Researcher Dr Jingjing Yu.
“One of the small molecules that produced the supramolecular plastic was previously screened out from a complex chemical system. It formed smart hydrogel materials with magnesium metal cations. This time, we are very excited to teach this old molecule new tricks with LLPS,” says the Principal Investigator of the laboratory, Dr Jianwei Li.
“Emerging evidence has shown that LLPS could be a significant process during the formation of cell compartments. Now, we advanced this bio- and physical-inspired phenomenon to tackle the grand challenge for our environment. I believe that more interesting materials will be explored with the LLPS process in the near future,” Li continues.
New Multisensory Hybrid Material
A physicist at the TU Graz University in Austria has developed an electronic skin which is similar to human skin. The new multisensory hybrid material is capable of sensing pressure, humidity and temperature simultaneously and produces electronic signals.
For almost six years, the team worked on the development of smart skin as part of Coclite’s ERC project Smart Core. With 2,000 individual sensors per square mm, the hybrid material is even more sensitive than a human fingertip. Each of these sensors consists of a unique combination of materials: a smart polymer in the form of a hydrogel inside and a shell of piezoelectric zinc oxide.
Coclite explains: “The hydrogel can absorb water and thus expands upon changes in humidity and temperature. In doing so, it exerts pressure on the piezoelectric zinc oxide, which responds to this and all other mechanical stresses with an electrical signal.” The result is a wafer-thin material that reacts simultaneously to force, moisture and temperature with extremely high spatial resolution and emits corresponding electronic signals.
The individual sensor layers are very thin and at the same time equipped with sensor elements covering the entire surface. This was possible in a worldwide unique process for which the researchers combined three known methods from physical chemistry for the first time: a chemical vapor deposition for the hydrogel material, an atomic layer deposition for the zinc oxide and nanoprint lithography for the polymer template. The lithographic preparation of the polymer template was the responsibility of the research group ‘Hybrid electronics and structuring’ headed by Barbara Stadlober. The group is part of Joanneum Research’s Materials Institute based in Weiz.
Several fields of application are now opening up for the skin-like hybrid material. In healthcare, for example, the sensor material could independently detect microorganisms and report them accordingly. Also conceivable are prostheses that give the wearer information about temperature or humidity, or robots that can perceive their environment more sensitively. On the path to application, smart skin scores with a decisive advantage: the sensory nanorods – the ‘smart core’ of the material – are produced using a vapor-based manufacturing process. This process is already well established in production plants for integrated circuits, for example. The production of smart skin can thus be easily scaled and implemented in existing production lines.
New Insulating Material from Wood Better than Plastic-Based Materials
Researchers at the Wallenberg Wood Science Center at the KTH Royal Institute of Technology in Sweden have developed a new insulating material from wood which offers better thermal performance than plastic-based insulation materials.
Assistant professor Yuanyuan Li says that the new insulating material is an aerogel integrated wood which is made without adding additional substances. Wood cellulose aerogels themselves are nothing new but Li says the new method represents a breakthrough in controlled creation of insulating nanostructures in the pores of wood.
The process starts with delignifying the wood—that is, removing the lignin which gives wood its color and strength, leaving behind empty pores or lumen. Reducing thermal conductivity in the material is done by taking the next step—getting inside these large empty pores and generating more nano pores inside of them—thousands of them, in fact.
These nanoporous structures are created by partial dissolution of the cell walls followed by controlled precipitation, she says. An ionic liquid (IL) mixture is added to partially dissolve the cell wall before water is added, which generates nanofibril networks that render the lumen nanoporous.
Li says the researchers developed a high level of control over the precipitation process, which means they can create the precise level of nanoporosity to achieve ideal thermal conductivity.
Building insulation isn’t the only potential use for the aerogel. Li says the unique structure enables advanced materials for energy storage and conversion, and even tissue engineering. “In packaging, for example, plastic foam such as polystyrene helps prevent heat transfer between objects and the surrounding environment, so it can keep goods cool during the shipment,” she says.
“But in situ formation of nanofibril networks inside wood’s empty spaces can result in wood being highly thermal insulating.”
Battery Separator Made from Seaweed-based Nanomaterials
Bristol-led team uses nanomaterials made from seaweed to create a strong battery separator, paving the way for greener and more efficient energy storage. Sodium-metal batteries (SMBs) are one of the most promising high-energy and low-cost energy storage systems for the next-generation of large-scale applications. However, one of the major impediments to the development of SMBs is uncontrolled dendrite growth, which penetrate the battery’s separator and result in short-circuiting.
Building on previous work at the University of Bristol and in collaboration with Imperial College and University College London, the team has succeeded in making a separator from cellulose nanomaterials derived from brown seaweed. The research describes how fibres containing these seaweed-derived nanomaterials not only stop crystals from the sodium electrodes penetrating the separator, they also improve the performance of the batteries.
“The aim of a separator is to separate the functioning parts of a battery (the plus and the minus ends) and allow free transport of the charge. We have shown that seaweed-based materials can make the separator very strong and prevent it from being punctured by metal structures made from sodium. It also allows for greater storage capacity and efficiency, increasing the lifetime of the batteries - something which is key to powering devices such as mobile phones for much longer,” said Jing Wang, first author and PhD student in the Bristol Composites Institute (BCI).
Dr. Amaka Onyianta, also from the BCI, who created the cellulose nanomaterials and co-authored the research, said: “I was delighted to see that these nanomaterials are able to strengthen the separator materials and enhance our capability to move towards sodium-based batteries. This means we wouldn’t have to rely on scarce materials such as lithium, which is often mined unethically and uses a great deal of natural resources, such as water, to extract it.”
“This work really demonstrates that greener forms of energy storage are possible, without being destructive to the environment in their production,” said Professor Steve Eichhorn who led the research at the Bristol Composites Institute. The next challenge is to upscale production of these materials and to supplant current lithium-based technology.
Sustainable Thin-Film Composite Membrane Made from Shrimp Shells
Shrimp shells, plant extracts and recycled plastic have helped Kaust researchers to build a sustainable thin-film composite membrane that could replace conventional membranes whose environmental toll is greater. Thin-film composite membranes are widely used in applications such as wastewater treatment, gas separation and chemicals production. They include a porous support topped by an ultrathin layer containing nanoscale pores that can trap molecules and tiny particles while allowing liquid solvents to pass through.
Most of these membranes are made using materials derived from fossil fuels, some of which are toxic. So, a research team led by Gyorgy Szekely set out to re-engineer these membranes using green materials and processes. The team made the porous support using recycled plastic and coated this with a natural nontoxic polymer called chitosan, derived from shrimp shells. The National Aquaculture Group (Naqua) in Saudi Arabia produces about 50,000 tons of shrimp shell waste annually, which is used to produce 135 tons of chitosan per year.
To form chitosan into a nanoporous membrane, the team cross-linked its polymer chains using 2,5-furandicarboxaldehyde (FDA), a molecule derived from plant waste via green processes. The researchers selected eucalyptol, produced from the leaves of the eucalyptus tree, as the solvent for this reaction. They also used a catalyst called TMG, a greener alternative to the harsh compounds typically used to speed up the cross-linking.
“Converting abundantly available waste biomass into value-added materials, such as this membrane, not only solves a waste-management issue but also generates a value-added product,” says Szekely. Using waste materials also means the new membrane has a similar cost to conventional membranes, he adds.
After optimizing the membrane preparation process, the researchers tested the membranes using a solvent called acetone that carried polystyrene molecules of different lengths, along with a smaller molecule called methyl styrene dimer. The membrane allowed acetone to flow through at a similar rate to conventional membranes. “It can also filter out molecules of an equivalent size to dyes or active pharmaceutical ingredients,” says Cong Yang, a Ph.D. student in the team. “Therefore, this membrane is practically applicable for biomedical, textile, pharmaceutical or food industries.”
The researchers also showed they could fine-tune the membrane’s properties with a nontoxic solvent called TamiSolve. They now hope to collaborate with local shrimp farms to ensure a sustainable supply of chitosan, as well as develop processes to make the membranes on a larger scale.