Broadband and pixelated camouflage in inflating chiral nematic liquid crystalline elastomers
Source abstract
Abstract
Living organisms such as fishes1, cephalopods2 and clams3 are cryptically coloured with a wide range of hues and patterns for camouflage, signalling or energy regulation. Despite extensive efforts to create colour-changing materials and devices4, it is challenging to achieve pixelated structural coloration with broadband spectral shifts in a compact space. Here, we describe pneumatically inflating thin membranes of main-chain chiral nematic liquid crystalline elastomers that have such properties. By taking advantage of the large elasticity anisotropy and Poisson's ratio (>0.5) of these materials, we geometrically program the size and the layout of the encapsulated air channels to achieve colour shifting from near-infrared to ultraviolet wavelengths with less than 20% equi-biaxial transverse strain. Each channel can be individually controlled as a colour 'pixel' to match with surroundings, whether periodically or irregularly patterned. These soft materials may find uses in distinct applications such as cryptography, adaptive optics and soft robotics.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Liquid Crystal Research Advancements · Advanced Materials and Mechanics · Tactile and Sensory Interactions
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (38)
Show source-provided references
1. Brady, P. C. et al. Open-ocean fish reveal an omnidirectional solution to camouflage in polarized environments. Science 350, 965–969 (2015).10.1126/science.aad5284 ↗
2. Hanlon, R. Cephalopod dynamic camouflage. Curr. Biol. 17, R400–R404 (2007).10.1016/j.cub.2007.03.034 ↗
3. Kim, H. N., Vahidinia, S., Holt, A. L., Sweeney, A. M. & Yang, S. Geometric design of scalable forward scatterers for optimally efficient solar transformers. Adv. Mater. 29, 1702922 (2017).10.1002/adma.201702922 ↗
4. Morin, S. A. et al. Camouflage and display for soft machines. Science 337, 828–832 (2012).10.1126/science.1222149 ↗
5. Chan, E. P., Walish, J. J., Urbas, A. M. & Thomas, E. L. Mechanochromic photonic gels. Adv. Mater. 25, 3934–3947 (2013).10.1002/adma.201300692 ↗
6. Huang, C. & Chen, L. Negative Poisson’s ratio in modern functional materials. Adv. Mater. 28, 8079–8096 (2016).10.1002/adma.201601363 ↗
7. Ting, T. C. T. & Chen, T. Poisson’s ratio for anisotropic elastic materials can have no bounds. Q. J. Mech. Appl. Math. 58, 73–82 (2005).10.1093/qjmamj/hbh021 ↗
8. Peel, L. D. Exploration of high and negative Poisson’s ratio elastomer-matrix laminates. Phys. Status Solidi 244, 988–1003 (2007).10.1002/pssb.200572717 ↗
9. Hirota, Y., Ji, Y., Serra, F., Tajbakhsh, A. R. & Terentjev, E. M. Effect of crosslinking on the photonic bandgap in deformable cholesteric elastomers. Opt. Express 16, 5320–5331 (2008).10.1364/OE.16.005320 ↗
10. Zhang, P., Shi, X., Schenning, A. P. H. J., Zhou, G. & Haan, L. T. A patterned mechanochromic photonic polymer for reversible image reveal. Adv. Mater. Interfaces 7, 1901878 (2020).10.1002/admi.201901878 ↗
11. Mistry, D. et al. Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer. Nat. Commun. 9, 5095 (2018).10.1038/s41467-018-07587-y ↗
12. Mao, Y., Terentjev, E. M. & Warner, M. Cholesteric elastomers: deformable photonic solids. Phys. Rev. E 64, 041803 (2001).10.1103/PhysRevE.64.041803 ↗
13. Bermel, P. A. & Warner, M. Photonic band structure of highly deformable self-assembling systems. Phys. Rev. E 65, 010702 (2001).10.1103/PhysRevE.65.010702 ↗
14. Eubanks, R. & Sternberg, E. On the axisymmetric problem of elasticity theory for a medium with transverse isotropy. Indiana Univ. Math. J. 3, 89–101 (1954).10.1512/iumj.1954.3.53006 ↗
15. Serra, F., Matranga, M. A., Ji, Y. & Terentjev, E. M. Single-mode laser tuning from cholesteric elastomers using a “notch” band-gap configuration. Opt. Express 18, 575–581 (2010).10.1364/OE.18.000575 ↗
16. Gorodtsov, V. A. & Lisovenko, D. S. Extreme values of Young’s modulus and Poisson’s ratio of hexagonal crystals. Mech. Mater. 134, 1–8 (2019).10.1016/j.mechmat.2019.03.017 ↗
17. Stoney, G. G. The tension of metallic films deposited by electrolysis. Proc. R. Soc. A 82, 172–175 (1909).
18. Ghoshal, A., DeMartini, D. G., Eck, E. & Morse, D. E. Optical parameters of the tunable Bragg reflectors in squid. J. R. Soc. Interface 10, 20130386 (2013).10.1098/rsif.2013.0386 ↗
19. Xia, Y., Zhang, X. & Yang, S. Instant locking of molecular ordering in liquid crystal elastomers by oxygen-mediated thiol–acrylate click reactions. Angew. Chem. Int. Ed. 57, 5665–5668 (2018).10.1002/anie.201800366 ↗
20. Liu, J. et al. Shaping and locomotion of soft robots using filament actuators made from liquid crystal elastomer–carbon nanotube composites. Adv. Intell. Syst. 2, 1900163 (2020).10.1002/aisy.201900163 ↗
21. Kobashi, J., Yoshida, H. & Ozaki, M. Planar optics with patterned chiral liquid crystals. Nat. Photon. 10, 389–392 (2016).10.1038/nphoton.2016.66 ↗
22. Schmidtke, J., Kniesel, S. & Finkelmann, H. Probing the photonic properties of a cholesteric elastomer under biaxial stress. Macromolecules 38, 1357–1363 (2005).10.1021/ma0487655 ↗
23. Atkinson, M. Accurate determination of biaxial stress—strain relationships from hydraulic bulging tests of sheet metals. Int. J. Mech. Sci. 39, 761–769 (1997).10.1016/S0020-7403(96)00093-8 ↗
24. Arsenault, A. C. et al. From colour fingerprinting to the control of photoluminescence in elastic photonic crystals. Nat. Mater. 5, 179–184 (2006).10.1038/nmat1588 ↗
25. Teyssier, J., Saenko, S. V., Van Der Marel, D. & Milinkovitch, M. C. Photonic crystals cause active colour change in chameleons. Nat. Commun. 6, 6368 (2015).10.1038/ncomms7368 ↗
26. Cuthill, I. C. et al. Disruptive coloration and background pattern matching. Nature 434, 72–74 (2005).10.1038/nature03312 ↗
27. Cuthill, I. C. et al. Optimizing countershading camouflage. Proc. Natl Acad. Sci. USA 113, 13093–13097 (2016).10.1073/pnas.1611589113 ↗
28. Stuart-Fox, D., Newton, E. & Clusella-Trullas, S. Thermal consequences of colour and near-infrared reflectance. Philos. Trans. R. Soc. B 372, 20160345 (2017).10.1098/rstb.2016.0345 ↗
29. Xu, C., Stiubianu, G. T. & Gorodetsky, A. A. Adaptive infrared-reflecting systems inspired by cephalopods. Science 359, 1495–1500 (2018).10.1126/science.aar5191 ↗
30. Yuk, H. et al. Hydraulic hydrogel actuators and robots optically and sonically camouflaged in water. Nat. Commun. 8, 14230 (2017).10.1038/ncomms14230 ↗
31. Broer, D. J., Lub, J. & Mol, G. N. Wide-band reflective polarizers from cholesteric polymer networks with a pitch gradient. Nature 378, 467–469 (1995).10.1038/378467a0 ↗
32. Smith, T. & Guild, J. The C.I.E. colorimetric standards and their use. Trans. Opt. Soc. 33, 73–134 (1931).10.1088/1475-4878/33/3/301 ↗
33. Adams, G. G. & Nosonovsky, M. Contact modeling—forces. Tribol. Int. 33, 431–442 (2000).10.1016/S0301-679X(00)00063-3 ↗
34. Argatov, I. I. Depth-sensing indentation of a transversely isotropic elastic layer: second-order asymptotic models for canonical indenters. Int. J. Solids Struct. 48, 3444–3452 (2011).10.1016/j.ijsolstr.2011.08.011 ↗
35. Cho, H. et al. Intrinsically reversible superglues via shape adaptation inspired by snail epiphragm. Proc. Natl Acad. Sci. USA 116, 13774–13779 (2019).10.1073/pnas.1818534116 ↗
36. McKee, C. T., Last, J. A., Russell, P. & Murphy, C. J. Indentation versus tensile measurements of Young’s modulus for soft biological tissues. Tissue Eng. Part B Rev. 17, 155–164 (2011).10.1089/ten.teb.2010.0520 ↗
37. Kim, S.-H., Kim, Y.-C., Lee, S. & Kim, J.-Y. Evaluation of tensile stress-strain curve of electroplated copper film by characterizing indentation size effect with a single nanoindentation. Met. Mater. Int. 23, 76–81 (2017).10.1007/s12540-017-6461-y ↗
38. Mott, P. H. & Roland, C. M. Limits to Poisson’s ratio in isotropic materials. Phys. Rev. B 80, 132104 (2009).10.1103/PhysRevB.80.132104 ↗