Hard Material With Self-Healing Capability

Imagine a cellphone that can heal from cuts and scratches just like the human body can. For Chinese researcher Ming Yang and his team at the Harbin Institute of Technology, it’s not really a question of imagining anymore: They have developed a new kind of smart coating that manages to be both soft and hard, not unlike our own skin.

We designed a self-healing coating with a hardness that even approaches tooth enamel by mimicking the structure of epidermis,” Yang says. “This is the most desirable property combination in the current self-healing materials and coatings.”

As described in a paper published Wednesday in ACS Nano, this new material is far from the first smart coating, with previous research looking at both soft and hard coating options. Yang says there’s serious global need for better self-healing materials.

Nowadays people always talk about environment and energy,” he adds. “A self-healing material can help save a lot of money and energy using a smart, environmental friendly way. But the current self-healing materials and coatings are typically soft and wear out quickly. This can bring potential problems about the management of plastic waste.

This new material could solve those waste problems, as it comes closer than any predecessor to combining the flexibility of a soft coating and the resilience of a hard coating, without the short lifespan of the former or the brittleness of the latter. This could be the best of both worlds.

The trick is to use artificial materials in nature’s way,” explains Yang. “The multilayer structure is the key. By placing a hard layer containing graphene oxide on top of a soft layer, we create a smart hybridization you can get the most out of.”

The graphene oxide material used in the coating’s top layer is harder than skin cells, offering a toughness closer to that of teeth enamel. The amazing thing, according to Yang, is that the coating’s hard and soft layers are able to work together to create healing properties that neither could accomplish on its own.

Source: https://pubs.acs.org/

Clean Hydrogen Produced From Biomass

A team of scientists at the University of Cambridge has developed a way of using solar power to generate a fuel that is both sustainable and relatively cheap to produce. It’s using natural light to generate hydrogen from biomass. One of the challenges facing modern society is what it does with its waste products. As natural resources decline in abundance, using waste for energy is becoming more pressing for both governments and business. Biomass has been a source of heat and energy since the beginning of recorded history.  The planet’s oil reserves are derived from ancient biomass which has been subjected to high pressures and temperatures over millions of years. Lignocellulose is the main component of plant biomass and up to now its conversion into hydrogen has only been achieved through a gasification process which uses high temperatures to decompose it fully.

biomass can produce hydrogen

Lignocellulose is nature’s equivalent to armoured concrete. It consists of strong, highly crystalline cellulose fibres, that are interwoven with lignin and hemicellulose which act as a glue. This rigid structure has evolved to give plants and trees mechanical stability and protect them from degradation, and makes chemical utilisation of lignocellulose so challenging,” says  Dr Moritz Kuehnel, from the Department of Chemistry at the University of Cambridge and co-author of the research.

The new technology relies on a simple photocatalytic conversion process. Catalytic nanoparticles are added to alkaline water in which the biomass is suspended. This is then placed in front of a light in the lab which mimics solar light. The solution is ideal for absorbing this light and converting the biomass into gaseous hydrogen which can then be collected from the headspace. The hydrogen is free of fuel-cell inhibitors, such as carbon monoxide, which allows it to be used for power.

The findings have been  published in Nature Energy.

Source: http://www.cam.ac.uk/