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Synthesis and alignment of liquid crystalline elastomers

Nature Reviews Materials volume 7, pages 23–38 (2022)Cite this article

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Abstract

Liquid crystalline elastomers (LCEs) are crosslinked polymer networks that combine the elastic properties of rubber with the anisotropic properties of liquid crystals. Multifunctionality and responsivity can be programmed into LCEs by patterning their local orientation, which is difficult to achieve in other monolithic material systems. Advances in the synthesis and alignment of LCEs have paved the way for their functional integration in robotics, optics, consumer products, energy and healthcare devices. In this Review, we discuss recent advances in materials chemistry and processing that have contributed to the resurgence in LCE research. We examine the mechanical response of LCEs to stimuli and survey approaches for mechanical alignment, surface-enforced alignment, field-induced alignment and rheological alignment. The Review concludes with an over-the-horizon outlook discussing current challenges and emerging research opportunities.

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Fig. 1: Liquid crystalline elastomers as functional materials.
Fig. 2: Liquid crystalline polymer elastomers and networks.
Fig. 3: Liquid crystalline elastomers as actuators.
Fig. 4: Nonlinear deformation of liquid crystalline elastomers to load.
Fig. 5: Synthetic approaches for the preparation of crosslinked liquid crystalline polymers.
Fig. 6: Alignment of liquid crystalline elastomers.
Fig. 7: Direct ink writing of liquid crystalline elastomers.

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Acknowledgements

The authors acknowledge the financial support of the Army Research Office (ARO), Defense Advanced Research Projects Agency (DARPA), the Materials and Manufacturing Directorate of the Air Force Research Laboratory (AFRL) and the University of Colorado. H.E.F. acknowledges Graduate Research Fellowship support from the National Science Foundation. K.R.S. acknowledges support from the Department of Defense (DoD) through the National Defense Science and Engineering Graduate (NDSEG) Fellowship Program.

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  1. Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, USA

    Katie M. Herbert, Hayden E. Fowler, Joselle M. McCracken, Kyle R. Schlafmann, Jeremy A. Koch & Timothy J. White

  2. Materials Science & Engineering Program, University of Colorado Boulder, Boulder, CO, USA

    Timothy J. White

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Herbert, K.M., Fowler, H.E., McCracken, J.M. et al. Synthesis and alignment of liquid crystalline elastomers. Nat Rev Mater 7, 23–38 (2022). https://doi.org/10.1038/s41578-021-00359-z

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