Luminous helices

British researcher Catherine Killalea is spending two years as a postdoctoral researcher at the University of Angers, thanks to European funding. Together with her mentor, David Canevet, she will explore the properties of helical molecules for possible advances in display and imaging.

Catherine Killalea and David Canevet in one of the Moltech laboratories.

At the  Moltech-Anjou research unit, Marc Sallé and David Canevet have been working for several years on foldamers, linear molecules that fold into helical shapes. They generally take the form of a single helical structure, much like a corkscrew, but can also form a double helix in response to a stimulus (light or electric current), "like DNA or the double spiral staircase in the Château de Chambord," explains David Canevet, professor of organic and supramolecular chemistry and a specialist in stimulable functional architectures.

In 2019, his work took him to Nottingham. Instead of meeting Robin Hood, he met Catherine Killalea, who was working on her thesis in a team specialising in chiral materials and luminescence. Chiral objects cannot be superimposed on their mirror images, like our hands. But chirality can take more complex forms, especially helical ones, like in foldamers.

With the support of Cap Europe, UA's European project set-up and management service, David Canevet and Catherine Killalea, known as 'Lizzie', are currently running the 'Skyfall' project in Angers, a reference to James Bond and the codename for: Stimuli-responsive chiral foldamers in solution and light-emitting diode . It is funded by the European Commission for 2 years, until the end of 2025, with €196,000 under the Marie Skłodowska-Curie Actions (MSCA Postdoctoral Fellowships).

Light control

The young British researcher, who has just completed a two-year experiment in a Belgian laboratory, and her mentor will "customise" the foldamers by adding patterns that change shape when exposed to light. "We want to graft fluorescent or phosphorescent compounds onto the foldamers and then use their chirality to emit circularly polarised light," explains the duo. "We can choose whether the helices are single or double, which allows us to control, for example, the colour and intensity of the emission."

This fundamental work could have potential applications in imaging (contrast agents) or electronics. "Oled screens are very good today, but there is still progress to be made in terms of contrast, which could be made possible by circularly polarised light," notes David Canevet. "The development of future generations of screens could be based on this phenomenon."