4D printing of fast-responsive liquid crystalline elastomers for light-driven actuators

Year: 2026

Authors: Simonetti G., Rossi R., Martella D., Credi C., Ferrantini C., Carpi F., Parmeggiani C.

Autors Affiliation: European Lab Non Linear Spect LENS, Sesto Fiorentino, FI, Italy; Univ Florence, Dept Physiscs & Astron, Sesto Fiorentino, Italy; Univ Florence, Dept Chem Ugo Schiff, Sesto Fiorentino, Italy; Natl Res Council INO CNR, Natl Inst Opt, Sesto Fiorentino, Italy; Univ Florence, Dept Expt & Clin Med, Florence, Italy; Univ Florence, Dept Ind Engn, Florence, Italy.

Abstract: Among smart materials, Liquid Crystalline Elastomers (LCEs) combine programmable well-defined deformations with wireless control. To date, the successful fabrication of LCEs through 3D printing techniques, such as direct ink writing (DIW), requires precise control over the ink formulation, mesogen alignment, and curing processes, to get devices with uniform molecular orientations, and with optimized actuation performance. Here, we present a simple synthetic approach leading to a ten-of-gram-scale ink production suitable for low-cost DIW 3D printing of LCEs. The novel ink, containing a push-pull azobenzene directly linked to the polymer backbone, enabled 4D printing of fast responsive photo-mechanical actuators with programmable and reversible deformation. Our centimeter-scale LCE structures present active tensions twitches comparable to those of cardiac muscles, both in terms of magnitude (kPa range) and timescale (tens to hundreds of milliseconds). An all-round actuation characterization is also developed and reported. As a proof-of-concept demonstrator, an optical beam steerer was developed demonstrating a high control of the beam diffraction angle as a function of the control beam light power.

Journal/Review: RESPONSIVE MATERIALS

More Information: This work has received funding from the European Union under the Horizon 2020 research and innovation programme, grant agreement No. 95216 (REPAIR), and from the European Union-NextGenerationEU under the National Recovery and Resilience Plan (PNRR)-Mission 4 Education and research-Component 2 From research to business-Investment 1.1 Notice Prin 2022-DD N. 104 del 02/02/2022, from the project ALICE-light-Activated high-performance actuators by electrospinning of reversibly crosslinked Liquid CrystallinE networks, proposal code 20224EBZ3Y-CUP J53D23008450006. The financial support provided by the MUR-Dipartimenti di Eccellenza 2023-2027 to the Department of Chemistry Ugo Schiff (DICUS 2.0) and to the Department of Experimental and Clinical Med icine of the University of Florence is acknowledged. Finanziamento di Ateneo Unifi Grandi Attrezzature 2021 was also acknowledged.
KeyWords: 4D printing; light-actuation; liquid crystalline elastomers; photoresponsive materials; smart polymers
DOI: 10.1002/rpm2.70039