Abstract
Controlling the alignment of various functional molecules is important for the development of many next-generation, high-performance optical devices. However, there are some limitations in inducing molecular alignment using the current methods. We report herein the alignment control of azobenzene in a polymer film by a simple, new alignment-patterning technique based on a scanning wave photopolymerization (SWaP) concept. In this technique, molecular alignment was induced by the spatiotemporal control of the non-polarized light. A photoisomerizable azobenzene molecule, Disperse Red 1 (DR1), was doped into the photopolymerizable mixture, and it was successfully aligned along the direction of the neighboring mesogens; the alignment was induced by SWaP with unpolarized light. The alignment behavior showed that the degree of photoisomerization of the doped azobenzene moieties was proportional to the light intensity, and the unidirectional alignment of DR1 was achieved through optimization of the photopolymerization conditions. This finding indicates that SWaP could be employed as a novel and simple fabrication process for preparing a wide variety of highly functional optical devices requiring alignment control.
Similar content being viewed by others
Log in or create a free account to read this content
Gain free access to this article, as well as selected content from this journal and more on nature.com
or
References
Lakes R. Materials with structural hierarchy. Nature. 1993;361:511–5.
White TJ, Broer DJ. Programmable and adaptive mechanics with liquid crystal polymer networks and elastomers. Nat Mater. 2015;14:1087–98.
O’Neill M, Kelly SM. Photoinduced surface alignment for liquid crystal displays. Appl Phys. 2003;33:R67–R84.
Kato T, Mizoshita N, Kishimoto K. Functional liquid-crystalline assemblies: self- organized soft materials. Angew Chem Int Ed. 2006;45:38–68.
Fleischmann E-K, Zentel R. Liquid-crystalline ordering as a concept in materials science: from semiconductors to stimuli-responsive devices. Angew Chem Int Ed. 2013;52:8810–27.
Whitesides GM, Grzybowski B. Self-assembly at all scales. Science. 2002;295:2418–21.
Yaroshchuk O, Reznikov Y. Photoalignment of liquid crystals: basis and current trends. J Mater Chem. 2012;22:286–300.
Shishido A. Rewritable holograms based on azobenzene-containing liquid-crystalline polymers. Polym J. 2010;42:525–33.
Seki T, Nagano S, Hara M. Versatility of photoalignment techniques: from nematics to a wide range of functional materials. Polymer. 2013;54:6053–72.
Priimagi A, Barrett C, Shishido A. Recent twists in photoactuation and photoalignment control. J Mater Chem C. 2014;2:7155–62.
Ichimura K, Suzuki Y, Seki T, Hosoki A, Aoki K. Reversible change in alignment mode of nematic liquid crystals regulated photochemically by “command surfaces” modified with an azobenzene monolayer. Langmuir. 1988;4:1214–6.
Ichimura K. Photoalignment of liquid-crystal systems. Chem Rev. 2000;100:1847–73.
Natansohn A, Rochon P. Photoinduced motions in azo-containing polymers. Chem Rev. 2002;102:4139–76.
Seki T. New strategies and implications for the photoalignment of liquid crystalline polymers. Polym J. 2014;46:751–68.
Fukuhara K, Nagano S, Hara M, Seki T. Free-surface molecular command systems for photoalignment of liquid crystalline materials. Nat Commun. 2014;5:3320.
Seki T. Light-directed alignment, surface morphing and related processes: recent trends. J Mater Chem C. 2016;4:7895–910.
Schadt M, Schmitt K, Kozinkov V, Chigrinov V. Surface-induced parallel alignment of liquid crystals by linearly polymerized photopolymers. Jpn J Appl Phys. 1992;31:2155–64.
Schadt M, Seiberle H, Schuster A. Optical patterning of multi-domain liquid-crystal displays with wide viewing angles. Nature. 1996;381:212–5.
Chigrinov VG, Kozenkov VM, Kwok H-S. Photoalignment of liquid crystalline materials: physics and applications. Hoboken, NJ: John Wiley & Sons; 2008.
Kawatsuki N. Photoalignment and photoinduced molecular reorientation of photosensitive materials. Chem Lett. 2011;40:548–54.
Minami S, Kondo M, Kawatsuki N. Fabrication of UV-inactive photoaligned films by photoinduced orientation of H-bonded composites of non-photoreactive polymer and cinnamate derivative. Polym J. 2016;48:267–71.
Bushuyev, OS, Aizawa, M, Shishido, A, Barrett, CJ Shape-shifting azo dye polymers: towards sunlight-driven molecular devices. Macromol Rapid Commun. 2018;39:1700253.
Usui K, Katayama E, Wang J, Hisano K, Akamatsu N, Shishido A. Effect of surface treatment on molecular reorientation of polymer-stabilized liquid crystals doped with oligothiophene. Polym J. 2017;49:209–14.
Todorov T, Nikolova L, Tomova N. Polarization holography. 1: a new high-efficiency organic material with reversible photoinduced birefringence. Appl Opt. 1984;23:4309–12.
Crawford GP, Eakin JN, Radcliffe MD, Callan-Jones A, Pelcovits A. Liquid-crystal diffraction gratings using polarization holography alignment techniques. J Appl Phys. 2005;98:123102.
Ishiguro M, Sato D, Shishido A, Ikeda T. Bragg-type polarization gratings formed in thick polymer films containing azobenzene and tolane moieties. Langmuir. 2007;23:332–8.
de Haan LT, Sánchez-Somolinos C, Bastiaansen SMW, Schenning APHJ, Broer DJ. Engineering of complex order and the macroscopic deformation of liquid crystal polymer networks. Angew Chem Int Ed. 2012;51:12469–72.
Ware TH, McConney ME, Wie JJ, Tondiglia VP, White TJ. Voxelated liquid crystal elastomers. Science. 2015;347:982–4.
Palagi S, Mark AG, Reigh SY, Melde K, Qiu T, Zeng H, Parmeggiani C, Martella D, Sanchez-Castillo A, Kapernaum N, Giesselmann F, Wiersma DS, Lauga E, Fischer P. Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots. Nat Mater. 2016;15:647–54.
Hisano K, Kurata Y, Aizawa M, Ishizu M, Sasaki T, Shishido A. Alignment layer-free molecular ordering induced by masked photopolymerization with non-polarized light. Appl Phys Express. 2016;9:072601.
Hisano K, Aizawa M, Ishizu M, Kurata Y, Nakano W, Akamatsu N, Barrett CJ, Shishido A. Scanning wave photopolymerization enables dye-free alignment patterning of liquid crystals. Sci Adv. 2017;3:e1701610.
Krongauz VV, Legere-Krongauz CC. Morphological changes during anisotropic photopolymerization. Polymer. 1993;34:3614–9.
Broer DJ, Lub J, Mol GN. Wide-band reflective polarizers from cholesteric polymer networks with a pitch gradient. Nature. 1995;378:467–9.
Leewis CM, de Jong AM, van IJzendoorn LJ, Broer DJ. Reaction-diffusion model for the preparation of polymer gratings by patterned ultraviolet illumination. J Appl Phys. 2004;95:4125–39.
Jiang P, Bertone JF, Hwang KS, Colvin VL. Single-crystal colloidal multilayers of controlled thickness. Chem Mater. 1999;11:2132–40.
Demus D, Goodby J, Gray GW, Spiess HW, Vill V. Handbook of Liquid Crystals. Weinheim, Germany: Wiley-VCH; 1998.
Tawa K, Knoll W. Out-of-plane photoreorientation of azo dyes in polymer thin films studied by surface plasmon resonance spectroscopy. Macromolecules. 2002;35:7018–23.
Han M, Morino S, Ichimura K. Factors affecting in-plane and out-of-plane photoorientation of azobenzene side chains attached to liquid crystalline polymers induced by irradiation with linearly polarized light. Macromolecules. 2000;33:6360–71.
Meier JG, Ruhmann R, Stumpe J. Planar and homeotropic alignment of LC polymers by the combination of photoorientation and self-organization. Macromolecules. 2000;33:843–50.
Wu Y, Ikeda T, Zhang Q. Three-dimensional manipulation of an azo polymer liquid crystal with unpolarized light. Adv Mater. 1999;11:300–2.
Acknowledgements
This work was supported by the Precursory Research for Embryonic Science and Technology (PRESTO) program, “Molecular Technology and Creation of New Functions” (no. JPMJPR14K9), and the Japan Science and Technology Agency (JST). This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI grant no. JP17H05250 in Scientific Research on Innovative Areas “Photosynergetics.” This work was supported by JSPS KAKENHI grant no. JP17J09899. This work was performed under the Research Program for CORE Lab of “Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials” in the “Network Joint Research Center for Materials and Devices.” This work was performed under the Cooperative Research Program of “Network Joint Research Center for Materials and Devices.” This work was performed under the Research Program for Next Generation Young Scientists of “Network Joint Research Center for Materials and Devices: Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Rights and permissions
About this article
Cite this article
Aizawa, M., Hisano, K., Ishizu, M. et al. Unpolarized light-induced alignment of azobenzene by scanning wave photopolymerization. Polym J 50, 753–759 (2018). https://doi.org/10.1038/s41428-018-0058-2
Received:
Revised:
Accepted:
Published:
Version of record:
Issue date:
DOI: https://doi.org/10.1038/s41428-018-0058-2
