Readers of my blog have probably recognized that I write more about energy than about chemical developments. This is not by choice, but because I have over the last year found little to write about in the chemical world. Scouring, for example, Chemical and Engineering News’ annual issue of noteworthy chemical developments, I was somewhat underwhelmed, to coin a phrase, except perhaps in the pharma field, which I don’t write about. So, it was a really interesting to read about recent advances in the nanotechnology field that didn’t just announce, as is often the case, how a nanomaterial was added to a conventional material to achieve a special effect. (My skepticism appeared in a blog post dated Feb. 22, 2014 and other posts) The field of research I describe below covers a new area termed metamaterials: nanocomposite structures made up of metals or plastics that exhibit properties “not found in nature”.
The rather complex chart shown at left confirms the fact that very light materials (think aerosol foams) have little or no strength while the opposite is true at the other end. Materials selected for their tensile or compression strength tend to be heavy. The aim of this research was to find out whether it is possible to develop light materials that have much more strength than would be expected from their weight or density. At this point, if readers are interested and have the time, they might go to their computer and look at a presentation on Youtube by Dr. Julia Greer entitled Materials by Design: Three-dimensional nano-architected metamaterials.
Research has found that conventional materials like metals, glass, ceramics, etc exhibit quite different characteristics at nanoscale. Ceramics can be made stronger and much less brittle, glass fiber can be made ductile and most materials become much stronger(although they may also become weaker). When constructed into lattices, they can exhibit great strength while being essentially composed of 99+% air. Dr. Greer shows a picture of such a microlattice “brick” balanced on top of a blooming dandelion flower(!) Nanolattices can thus occupy a space on the chart well above that of materials in the lower left (Green) side of the diagram, with a strength 10 to 100 times that of materials with similar density. Preparation of these materials can involve technology similar to that used in 3D printers.
Commercial application of this technology may not be far away: promising areas include battery design, acoustical equipment, solar panels, medical imaging, etc. It will be interesting to see how quickly metamaterials find their way into our lives.