Sustainable Artificial Iridocytes for Designed Visual Appearance

Visual appearance (e.g. vibrant colouration) is important for communication in Nature.

A particularly interesting example is the aggregates of reflector cells, or so-called ""iridocytes"", found in marine creatures.

Iridocytes are combined in their skin to produce a wide variety of colour effects; depending on their individual properties and spatial arrangement, they can show intense colours when all iridocytes have same periodicity, or a bright white, when the optical response from differently coloured iridocytes is superimposed.Inspired by this natural strategy, the aim of this proposal is to produce artificial iridocytes.

This will be achieved by exploiting the inherent tendency of block copolymers to self-organise into periodic nanoscale structures in solution.

In particular, by allowing for this evaporation-driven process to occur within miniscule droplets, it will be possible to produce particles that reflect specific colours of light.

Analogous to natural iridocytes, by combining different populations of such particles into a film it will be possible to control the overall appearance.

Building on this concept, we will investigate how the shape of the particles and their ensemble arrangement can be used to introduce more sophisticated visual effects, from metallic or iridescent shine to a smooth matte appearance.

Finally, we will seek to develop 'smart' coatings, where the appearance can dynamically respond to a stimulus, such as magnetic field.Our novel approach to coloration has a broad range of potential commercial applications, like inks, paints, cosmetics, displays, sensors.

Importantly, by considering the life cycle of the polymers from the outset of the project we will ensure that the produced pigments are not only non-toxic, but also bio-compatible and bio-degradable.

This will allow us to respectively address the growing concerns regarding the safety of existing mineral-based pigments and the extent of environmental pollution by microplastics.