3D printed elastomers with stereochemically-defined properties

In most synthetic polymeric materials, control over the mechanical properties of the material is achieved by changing the fundamental chemical structure of the polymer by using monomers with fundamentally different functional groups, chain length or rigidity.

In contrast, Nature’s polymers use a more restricted set of building blocks but use additional complexity to the structure−property relationship by leveraging stereochemistry to control the structure and hence properties and function of materials.

Through the STEREOPOL ERC programme, we have been investigating this relationship and how to both overcome the synthetic limitations that hold back the design of stereoregular materials, as well as how these fundamental properties can be used to influence materials properties and behaviour.

Within this project, and inspired by the cis/trans stereochemistry that dictates the enormous differences in mechanical properties between the otherwise structurally identical gutta percha and natural rubber, we have discovered that E/Z isomerisism within double bonds in synthetically-accessible polymers can be used to control mechanical properties of the resultant thermoplastic elastomer materials.

Through this work, we have identified that these principles can be extended to photoset materials (those that are crosslinked by exposure to light), while retaining their elastomeric nature.

In turn, this advance enables us to develop the first 3-dimensional (3D) printed elastomers with material properties that are determined by stereochemical composition.

The ability to control materials properties by stereochemical leverage will reduce the need to reformulate each composition for processing by 3D printing, thus providing a significant commercial advantage in an area in which competitive materials are limited but in which there is a significant need.