Welcome Physics World  November 2021

Protecting the material world

Soon after this Physics World Materials Briefing goes to press, leaders from around the world will gather (virtually and in Glasgow, UK) for the 26th UN Climate Change Conference. Known informally as COP26, the conference has been billed as a make-or-break opportunity for politicians to sign up to tighter regulations on carbon emissions, and thereby stave off some of the worst consequences of human-induced climate change. 

Whatever the conference’s outcome, though, the interlinked issues of climate, pollution and energy are not going away, so it’s appropriate that all of them appear prominently in this briefing. Materials that generate and store low-carbon energy have long been a mainstay of Physics World’s environmental coverage, and the “Materials for energy” section keeps up this tradition with reports on lithium metal batteries; recyclable supercapacitors; and a combined solar energy and desalination system that produces solid salt, rather than liquid brine, as waste. In a similar vein, an interview with hybrid perovskite solar cell developer Giulia Grancini (‘In search of new solutions for cheap and stable solar cells’) explores ways of optimizing novel light-absorbing materials and incorporating them into the “smart cities” of the future.

Increasingly, though, research on “green” materials is also cropping up in sub-fields that lack such a long tradition of environmental consciousness. The lead article in the section on biomaterials (‘Wood-based coatings offer green soundproofing’), for example, shows how foam made from pulped wood, rather than carbon-intensive gypsum plasterboard, can improve the acoustics inside buildings. Another article in the same section explains how scientists at Duke University in the US used a suite of carbon-based materials – nanocellulose, graphene, and carbon nanotubes – to make the first non-toxic, fully recyclable transistors. And an article in the section on advanced materials (‘New material breaks low-thermal-conductivity record’) describes how a newly synthesized inorganic substance with the lowest thermal conductivity so far reported could support technologies that convert waste heat into power.

Researchers who study polymers and semiconductors are also finding ways to incorporate sustainability into their work. Svetlana Boriskina and colleagues at the Massachusetts Institute of Technology, US developed a new type of polyethylene fabric (‘Recycled plastic bags make sustainable fabric’) that is not only more breathable than cotton, but also has a smaller ecological footprint because it is so easy to manufacture, dye, clean and reuse. The self-healing circuit pictured above (‘Electronic circuits can now self-heal’) is made primarily from plastic, but it is specially designed to be durable and readily recycled – features that are crucial if humans are to benefit from the ubiquitous connectivity and sensing capabilities of the so-called “Internet of Things” without creating a new and damaging wave of quickly discarded electronics. With the unsettling conclusions of the latest UN Intergovernmental Panel on Climate Change (IPCC) report still fresh in the memory, it’s heartening to see researchers in so many areas of materials science working towards a more sustainable society.