Direct ink writing of liquid crystal elastomers (LCEs) offers a new opportunity to program geometries for a wide variety of shape transformations. However, the degree of shape change is highly dependent on the underlying heating stage: once out of the hot stage, the shape tends to return back to the original stage. Therefore, the ability to spatially actuate the 3D printed LCEs in free-forms is highly desired. Herein, we develop a 3D-printable gold nanorod (AuNR)/LCE composite ink, allowing for photothermal actuation of the printed filaments even at a low AuNR concentration (0.1 wt%). By fine-tuning the printing pressure, speed, and temperature, as well as the ink formulation, we show that the printed filament has superior photothermal response with 27 % actuation strain upon irradiation to near-infrared (NIR) light (808 nm) at 1.4 W/cm<sup>2</sup>, corresponding to 160 °C. As a result, each 3D printed AuNR/LCE composite lattice can be actuated into different shapes with high amplitudes by locally control of its exposure to NIR laser.

3D printing of photoresponsive gold nanorod/liquid crystal elastomer composites

ACS Spring 2022

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