21 April 2009

Beauty is skin deep

“These lenses have a surface coating,” said my partner, waving her spectacles at me, “and it’s a nightmare because it comes off. Stick that in your article!”

So I did (stick it in my article, that is), because it served to bring together and focus several different skeins of thought. Surface coating is one of the oldest human technologies, but still at the cutting edge and a prime consumer of scientific computing. Biomimetic or nanoscale, from reduction of optical reflections in lens systems to protection of components in orbit, taking in paper manufacture and dental treatment in between it is crucial to almost every area of endeavour. How might we make an optical surface coating less likely to come off? The obvious answer is improved adhesion, but to strengthen it or make it self-healing would be alternative approaches. After a detour through various mesoscale approaches it seems fairly certain that the answer, whatever it is, will lie in nanotechnology.

The archetypal adhesive surface coating is a protective layer of paint, pitch or varnish, first recorded in Genesis 6:14. Noah’s account lacks computational detail, but requirements for precision have certainly tightened since Cennini[1] specified, some time around the end of the 14th century CE: ‘take one pound, or two, or three, or four, of linseed oil, and put it into a new casserole...’ [more]

  • Cennino d'Andrea Cennini, trans D.V. Thompson, The craftsman's handbook : the Italian "Il libro dell'arte". 1960, New York,: Dover Publications. 048620054X (pbk.)