Stimuli-responsive materials can enhance the field of 3D printing by generating objects that change shape in response to external cues. While temperature and pH are common inputs for initiating a response in a 3D printed object, there are few examples of using a mechanical input to afford a response. We have developed a suite of ionic liquid gel inks that can be used to fabricate 3D printed objects that use a single mechanoactivation event to elicit both mechanochromic and mechanomorphic responses. Direct-ink write (DIW) 3D printing was used to deposit ionic liquid gel inks to create multimaterial objects that underwent a predetermined mechanoactivated shape change when the sample was pulled and then released. When spiropyran was incorporated into the inks, the onset of spiropyran isomerization into its purple merocyanine form occured at strains dependent upon the polymer network composition. The color onset could be used as a simple visual cure for the user as an indicator for the strain required to achieve a predetermined shape change. Such morphing 3D printed structures with integrated instructions have potential application to areas including stowable structures as well as multi-responsive autonomous components and sensors.

3D printed polymer networks with a mechanochromic and mechanomorphic response

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.