Easily Processable Temperature-Responsive Infrared-Reflective Polymer Coatings

A temperature-responsive near-infrared reflective coating was fabricated based on a side-chain liquid crystal siloxane polymer using a simple wired-bar method. The cholesteric liquid crystalline polymer film showed a blue shift of the reflection band of ∼1000 nm in the IR region upon heating. The temperature-responsive change of the reflection band was reversible. Compared to that of the same mixture system in an alignment cell, the coating showed a significantly faster response. This research demonstrates an easy way to prepare a temperature-responsive IR-reflective coating that shifts its reflection to a shorter wavelength upon heating. As IR radiation of shorter wavelengths is more strongly represented in sunlight than longer wavelengths, this coating could be used to selectively reduce heating of an indoor space when the temperature is high. This is promising for the future application of smart climate control.

[1]  K. Urayama,et al.  Thermal response of cholesteric liquid crystal elastomers. , 2015, Physical review. E, Statistical, nonlinear, and soft matter physics.

[2]  Jlm Jan Hensen,et al.  Climate adaptive building shells: state-of-the-art and future challenges , 2013 .

[3]  J. Baumberg,et al.  Nanoparticle-tuned structural color from polymer opals. , 2007, Optics express.

[4]  S.-Y.T. Tzeng,et al.  Thermal tuning band gap in cholesteric liquid crystals , 2010 .

[5]  Arno Seeboth,et al.  Thermochromic polymers--function by design. , 2014, Chemical reviews.

[6]  H. Kawaguchi.  Thermoresponsive microhydrogels: preparation, properties and applications , 2014 .

[7]  I. Dierking,et al.  TGB A* state in a homologous series of diarylethane α-chloroester ferroelectric liquid crystals , 1994 .

[8]  Bao‐yan Zhang,et al.  Synthesis and properties of novel chiral side-chain liquid crystalline polysiloxanes containing different chiral pendant groups , 2013, Journal of Materials Science.

[9]  Haifeng Yu,et al.  Polymeric infrared reflective thin films with ultra-broad bandwidth , 2016 .

[10]  Ryan C Hayward,et al.  Photonic Multilayer Sensors from Photo‐Crosslinkable Polymer Films , 2012, Advanced materials.

[11]  J. Goodby,et al.  A new molecular ordering in helical liquid crystals , 1989 .

[12]  Shin-Tson Wu,et al.  Tuning the photonic band gap in cholesteric liquid crystals by temperature-dependent dopant solubility. , 2006, Optics express.

[13]  T. Kajiyama,et al.  Thermal switching characteristics based on smectic-A↔chiral nematic phase transitions of (liquid crystals/chiral dopant) composites, with and without side chain-type liquid crystalline polymer , 2002 .

[14]  M. Torkkeli,et al.  Self-assembled polymeric solid films with temperature-induced large and reversible photonic-bandgap switching , 2004, Nature materials.

[15]  G. Chilaya.  Effect of various external factors and pretransitional phenomena on structural transformations in cholesteric liquid crystals , 2000 .

[16]  E. Thomas,et al.  Thermochromic Block Copolymer Photonic Gel , 2008 .

[17]  Thermochromic polymer opals , 2009, CLEO/QELS: 2010 Laser Science to Photonic Applications.

[18]  Lalgudi V. Natarajan,et al.  Electro-thermal tuning in a negative dielectric cholesteric liquid crystal material , 2008 .

[19]  Hitesh Khandelwal,et al.  Infrared reflector based on liquid crystal polymers and its impact on thermal comfort conditions in buildings , 2014, Optics & Photonics - Photonic Devices + Applications.

[20]  I. Dierking,et al.  Cholesteric pitch divergence near smectic phase transitions. , 2010, Physical review. E, Statistical, nonlinear, and soft matter physics.

[21]  A. Schenning,et al.  Application of broadband infrared reflector based on cholesteric liquid crystal polymer bilayer film to windows and its impact on reducing the energy consumption in buildings , 2014 .

[22]  Ben L Feringa,et al.  Amplification of chirality in liquid crystals. , 2006, Organic & biomolecular chemistry.

[23]  Kazuhide Ueno,et al.  An Electro‐ and Thermochromic Hydrogel as a Full‐Color Indicator , 2007 .

[24]  Super wide-band reflective polarisers from polymer stabilised liquid crystal films , 2009 .

[25]  Y. Fainman,et al.  Near-perfect broadband absorption from hyperbolic metamaterial nanoparticles , 2017, Proceedings of the National Academy of Sciences.

[26]  H. Hakemi.  Industrial Development of Plastic PDLC: Is There a Future? , 1998 .

[27]  G. Chilaya.  Always Cholesterics…but Sometimes Chiral Smectic C, TGB and Blue Phases , 2012 .

[28]  H. Cao,et al.  Control homogeneous alignment of chiral nematic liquid crystal with smectic-like short-range order by thermal treatment , 2012 .

[29]  Yang Wang,et al.  Switchable Materials for Smart Windows. , 2016, Annual review of chemical and biomolecular engineering.

[30]  P. Davidson.  X-ray diffraction by liquid crystalline side-chain polymers , 1996 .

[31]  Dirk J. Broer,et al.  Stimuli-responsive photonic polymer coatings. , 2014, Chemical communications.

[32]  Stephen D. Jacobs,et al.  Cholesteric Liquid Crystal Flakes — A New Form of Domain , 1998 .

[33]  Michel Mitov,et al.  Color selectivity lent to a cholesteric liquid crystal by monitoring interface-induced deformations , 2011 .

[34]  K. Mainusch,et al.  Selektive Lichtreflexion an cholesterischen Flüssigkristallen , 1975 .

[35]  Jian Sun,et al.  Preparation and thermo-optical characteristics of a smart polymer-stabilized liquid crystal thin film based on smectic A–chiral nematic phase transition , 2014 .

[36]  N. Tamaoki,et al.  Study of Chiral Dimesogens: Liquid Crystalline Properties, Effect of Smectic Cybotactic Domains in Controlling the Chiral Reflections and Glassy Liquid Crystal Forming Properties , 2006 .

[37]  K. A. Suresh,et al.  Optical and X-ray Studies on the Twisted Smectic C and Twisted Nematic Phases: Evidence for a Skew-Cybotactic Type of Cholesteric Structure , 1977 .

[38]  H. Finkelmann,et al.  Investigations on liquid crystalline polysiloxanes, 2. Optical properties of cholesteric phases and influence of the flexible spacer on the mobility of the mesogenic groups†‡ , 1980 .

[39]  H. Ringsdorf,et al.  Liquid crystalline side chain polymers with low glass transition temperatures , 1982 .

[40]  S. Nagano,et al.  Inducing Planar Orientation in Side‐Chain Liquid‐Crystalline Polymer Systems via Interfacial Control , 2016, Chemical record.

[41]  T. Kurokawa,et al.  Lamellar Hydrogels with High Toughness and Ternary Tunable Photonic Stop‐Band , 2013, Advanced materials.

[42]  H. Yamane,et al.  Investigation of the electrothermo‐optical effect of a smectic LCP–nematic LC–chiral dopant ternary composite system based on SA ↔ N* phase transition , 1999 .

[43]  S. Furumi,et al.  Photoresponsive Glass‐Forming Butadiene‐Based Chiral Liquid Crystals with Circularly Polarized Photoluminescence , 2008 .

[44]  D.-K. Yang,et al.  Temperature dependence of pitch and twist elastic constant in a cholesteric to smectic A phase transition , 2002 .

[45]  P. D. Gennes,et al.  An analogy between superconductors and smectics A , 1972 .

[46]  H. Cao,et al.  Effect of cholesteric liquid crystalline elastomer with binaphthalene crosslinkings on thermal and optical properties of a liquid crystal that show smectic A-cholesteric phase transition , 2013 .

[47]  P. Sixou,et al.  Preparation and characteristics of cholesteric gel from pentyl ether of hydroxypropyl cellulose , 1995 .

[48]  H. Finkelmann,et al.  Liquid crystal side chain polymers , 1984 .

[49]  Michael G. Debije,et al.  Infrared Regulating Smart Window Based on Organic Materials , 2017 .

[50]  S. Lagerwall,et al.  INVESTIGATIONS OF THE STRUCTURE OF A CHOLESTERIC PHASE WITH A TEMPERATURE INDUCED HELIX INVERSION AND OF THE SUCCEEDING SC-ASTERISK PHASE IN THIN LIQUID-CRYSTAL CELLS , 1993 .

[51]  H. Finkelmann,et al.  Phase transformations of liquid crystalline side-chain oligomers , 1984 .