We set out to develop a prototype for icy road warning signs which was able to operate autonomously without the use of electricity, and which could be easily placed onto existing road features, such as street boundary pillars and road safety barriers.

The number of road accidents in the UK under frosty or icy conditions runs in the thousands. Our concept would aid to reduce these numbers, without the introduction of a digital, and thus electric, infrastructure.

The results from our studies are now published open access in the Journal of Materials Chemistry C from the Royal Society of Chemistry. The conceptual road sign application is a multi-lamellar flexible strip.

A temperature triggered response in the form of an upper critical solution temperature (UCST) type phase separation targeted near the freezing point of water manifests itself through light scattering as a clear-to-opaque transition. It is simultaneously amplified by an enhanced photoluminescence effect.