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Volume 22, Issue 2
  • ISSN: 1570-1794
  • E-ISSN: 1875-6271

Abstract

Cellulose nanocrystals (CNCs) have triggered considerable research interest in the last few years owing to their unique optical, biodegradation, and mechanical behavior. Herein, recent progress on the sensing application of photonic CNC films is summarized and discussed based on the analyses of the latest studies. We briefly introduce the three approaches for preparing CNCs: mechanical treatment, acid hydrolysis, and enzymatic hydrolysis, recapitulating their differences in preparation and properties. Then, when the aqueous suspension of cellulose nanocrystals (CNCs) reaches a specific concentration, it will self-assemble to form a left-handed nematic liquid crystal structure, and this structure can be maintained in films after water evaporation, which has strong photonic crystal properties. The periodic layered structure in the film interferes and diffracts with light, showing a rainbow color. Photonic CNC composites that combine CNCs and functional materials have good properties and broad prospects. Finally, we highlight the advanced applications of photonic CNC films, including mechanical sensing, thermal sensing, and humidity sensing. The prospects and ongoing challenges of photonic CNC films were summarized.

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2024-02-06
2025-04-24

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References

  1. SurovO.V. VoronovaM.I. ZakharovA.G. Functional materials based on nanocrystalline cellulose.Russ. Chem. Rev.2017861090793310.1070/RCR4745
     [Google Scholar]
  2. DumanliA.G. KamitaG. LandmanJ. van der KooijH. GloverB.J. BaumbergJ.J. SteinerU. VignoliniS. Controlled, bio‐inspired self‐assembly of cellulose‐based chiral reflectors.Adv. Opt. Mater.20142764665010.1002/adom.201400112 26229742
     [Google Scholar]
  3. LiY.Y. Preparation and application of nanocellulose and nanocellulose based functional materials.PhD Thesis, Nanjing Forestry University; Nanjing2004
     [Google Scholar]
  4. MoonR.J. MartiniA. NairnJ. SimonsenJ. YoungbloodJ. Cellulose nanomaterials review: Structure, properties and nanocomposites.Chem. Soc. Rev.20114073941399410.1039/c0cs00108b 21566801
     [Google Scholar]
  5. MedronhoB. LindmanB. Competing forces during cellulose dissolution: From solvents to mechanisms.Curr. Opin. Colloid Interface Sci.2014191324010.1016/j.cocis.2013.12.001
     [Google Scholar]
  6. NakagaitoA.N. YanoH. The effect of morphological changes from pulp fiber towards nano-scale fibrillated cellulose on the mechanical properties of high-strength plant fiber based composites.Appl. Phys., A Mater. Sci. Process.200478454755210.1007/s00339‑003‑2453‑5
     [Google Scholar]
  7. ChengW. ZhuY. JiangG. CaoK. ZengS. ChenW. ZhaoD. YuH. Sustainable cellulose and its derivatives for promising biomedical applications.Prog. Mater. Sci.202313810115210115210.1016/j.pmatsci.2023.101152
     [Google Scholar]
  8. WeiS. WanC. WuY. Recent advances in wood-based electrode materials for supercapacitors.Green Chem.20232593322335310.1039/D2GC04271A
     [Google Scholar]
  9. IslamM.S. ChenL. SislerJ. TamK.C. Cellulose nanocrystal (CNC)–inorganic hybrid systems: Synthesis, properties and applications.J. Mater. Chem. B Mater. Biol. Med.20186686488310.1039/C7TB03016A 32254367
     [Google Scholar]
  10. WeiH. RodriguezK. RenneckarS. VikeslandP.J. Environmental science and engineering applications of nanocellulose-based nanocomposites.Environ. Sci. Nano20141430231610.1039/C4EN00059E
     [Google Scholar]
  11. LiuP. Study on the self-assembly mechanism of cellulose nanocrystal under flow field and construction of its functional materials. PhD Thesis, Qingdao University Of Science And Technology; Tsingtao2017
     [Google Scholar]
  12. LiuY. Preparation and research of tempo oxidation nanocellulose and its composite film.Master Thesis, Inner MongoliaAgricultural University; Hohhot2020
     [Google Scholar]
  13. DaiL. Preparation and investigation of TEMPO-oxidized cellulose nanofibers and their composite films.PhD Thesis, Jiangnan University; Wuxi2015
     [Google Scholar]
  14. IsogaiA. SaitoT. FukuzumiH. TEMPO-oxidized cellulose nanofibers.Nanoscale201131718510.1039/C0NR00583E 20957280
     [Google Scholar]
  15. RohaizuR. WanrosliW.D. Sono-assisted TEMPO oxidation of oil palm lignocellulosic biomass for isolation of nanocrystalline cellulose.Ultrason. Sonochem.20173463163910.1016/j.ultsonch.2016.06.040 27773290
     [Google Scholar]
  16. QingY. WangL. WuY.Q. Formation and application of cellulose nanocrystal cholesteric phase liquid crystal.Linye Kexue20195504152159
     [Google Scholar]
  17. RolF. BelgacemM.N. GandiniA. BrasJ. Recent advances in surface-modified cellulose nanofibrils.Prog. Polym. Sci.20198824126410.1016/j.progpolymsci.2018.09.002
     [Google Scholar]
  18. ChuG. Cellulose nanocrystal-based chiral nematic material: A study on its optical properties.PhD Thesis, Jilin University; Changchun2016
     [Google Scholar]
  19. ShenP. TangQ. ChenX. LiZ. Nanocrystalline cellulose extracted from bast fibers: Preparation, characterization, and application.Carbohydr. Polym.202229011946211946210.1016/j.carbpol.2022.119462 35550763
     [Google Scholar]
  20. LiC.X. Optical-electrical properties and applications of novel cellulose liquid crystal nanomaterials.PhD Thesis, Zhejiang Universit; Hangzhou2021
     [Google Scholar]
  21. XueL. Preparation and property study of nanocrystalline cellulose cholesteric liquid crystal, film and oxide.Master Thesis, Nanjing Forestry University; Nanjing2012
     [Google Scholar]
  22. ErmakovS. BeletskiiA. EismontO. NikolaevV. Liquid Crystals in Biotribology: Synovial Joint Treatment.Cham, SwitzerlandSpringer International Publishing2016
     [Google Scholar]
  23. ChesterA.N. MartellucciS. Eds.;. Phase Transitions in Liquid Crystals.New YorkSpringer2014
     [Google Scholar]
  24. da RosaR.R. FernandesS.N. MitovM. GodinhoM.H. Cellulose and chitin twisted structures: From nature to applications.Adv. Funct. Mater.20232304286230428610.1002/adfm.202304286
     [Google Scholar]
  25. da RosaR.R. SilvaP.E.S. SaraivaD.V. KumarA. de SousaA.P.M. SebastiãoP. FernandesS.N. GodinhoM.H. Cellulose nanocrystal aqueous colloidal suspensions: Evidence of density inversion at the isotropic‐liquid crystal phase transition.Adv. Mater.20223428210822710.1002/adma.202108227 35502142
     [Google Scholar]
  26. LiY.Y.P. Preparation, properties and mechanism of cellulose nanocrystals/ waterborne polyurethane films.PhD Thesis, Beijing Forestry University; Beijing2021
     [Google Scholar]
  27. DuanM. Study on preparation and optical properties control of cellulose nanocrystals flexible iridescent film.Master Thesis, Shaanxi University of Science & Technology; Xian2019
     [Google Scholar]
  28. SelingerJ.V. Director deformations, geometric frustration, and modulated phases in liquid crystals.Annu. Rev. Condens. Matter Phys.2022131497110.1146/annurev‑conmatphys‑031620‑105712
     [Google Scholar]
  29. GençerA. SchützC. ThielemansW. Influence of the particle concentration and marangoni flow on the formation of cellulose nanocrystal films.Langmuir201733122823410.1021/acs.langmuir.6b03724 28034313
     [Google Scholar]
  30. HuangW.J. Preparation and anti-counterfeiting patterning of chiral nematic cellulose nanocrystals.Master Thesis, Tianjin University of Science and Technology; Tianjin2020
     [Google Scholar]
  31. DongX.M. KimuraT. RevolJ.F. GrayD.G. Effects of ionic strength on the isotropic−chiral nematic phase transition of suspensions of cellulose crystallites.Langmuir19961282076208210.1021/la950133b
     [Google Scholar]
  32. ChenQ. LiuP. NanF. ZhouL. ZhangJ. Tuning the iridescence of chiral nematic cellulose nanocrystal films with a vacuum-assisted self-assembly technique.Biomacromolecules201415114343435010.1021/bm501355x 25300554
     [Google Scholar]
  33. HuangY.Y. Preparation and properties of flexible water-resistant iridescent films based on cellulose nanocrystals. Master Thesis, South China University of Technology; Canton2020
     [Google Scholar]
  34. SehaquiH. LiuA. ZhouQ. BerglundL.A. Fast preparation procedure for large, flat cellulose and cellulose/inorganic nanopaper structures.Biomacromolecules20101192195219810.1021/bm100490s 20698565
     [Google Scholar]
  35. TranA. HamadW.Y. MacLachlanM.J. Fabrication of cellulose nanocrystal films through differential evaporation for patterned coatings.ACS Appl. Nano Mater.2018173098310410.1021/acsanm.8b00947
     [Google Scholar]
  36. Ureña-BenavidesE.E. AoG. DavisV.A. KitchensC.L. Rheology and phase behavior of lyotropic cellulose nanocrystal suspensions.Macromolecules201144228990899810.1021/ma201649f
     [Google Scholar]
  37. de VriesH. Rotatory power and other optical properties of certain liquid crystals.Acta Crystallogr.19514321922610.1107/S0365110X51000751
     [Google Scholar]
  38. LagerwallS.T. On some important chapters in the history of liquid crystals.Liq. Cryst.201340121698172910.1080/02678292.2013.831134
     [Google Scholar]
  39. NishioY. SatoJ. SugimuraK. Cellulose chemistry and properties: Fibers, nanocelluloses and advanced materials.Cham, SwitzerlandSpringer International Publishing2016
     [Google Scholar]
  40. BahrC. KitzerowH-S. Eds. Chirality in Liquid Crystals.New YorkSpringer-Verlag2001
     [Google Scholar]
  41. WangC. TangC. WangY. ShenY. QiW. ZhangT. SuR. HeZ. Chiral photonic materials self-assembled by cellulose nanocrystals.Curr. Opin. Solid State Mater. Sci.202226510101710.1016/j.cossms.2022.101017
     [Google Scholar]
  42. XueL. Preparation and property study of nanocrystalline cellulose cholesteric liquid crystal.NanjingFilm and Oxide2012
     [Google Scholar]
  43. TranA. BoottC.E. MacLachlanM.J. Understanding the self‐assembly of cellulose nanocrystals-toward chiral photonic materials.Adv. Mater.20203241190587610.1002/adma.201905876 32009259
     [Google Scholar]
  44. ChenJ. MaoL. QiH. XuD. HuangH. LiuM. WenY. DengF. ZhangX. WeiY. Preparation of fluorescent cellulose nanocrystal polymer composites with thermo-responsiveness through light-induced ATRP.Cellulose202027274375310.1007/s10570‑019‑02845‑8
     [Google Scholar]
  45. ShiZ. LiS. LiM. GanL. HuangJ. Surface modification of cellulose nanocrystals towards new materials development.J. Appl. Polym. Sci.2021138485155510.1002/app.51555
     [Google Scholar]
  46. SilvaP.E.S. ChagasR. FernandesS.N. PieranskiP. SelingerR.L.B. GodinhoM.H. Travelling colourful patterns in self-organized cellulose-based liquid crystalline structures.Commun. Mater.2021217910.1038/s43246‑021‑00182‑7
     [Google Scholar]
  47. AlmeidaA.P.C. CanejoJ.P. FernandesS.N. EcheverriaC. AlmeidaP.L. GodinhoM.H. Cellulose-based biomimetics and their applications.Adv. Mater.20183019170365510.1002/adma.201703655 29333680
     [Google Scholar]
  48. FernandesS.N. AlmeidaP.L. MongeN. AguirreL.E. ReisD. de OliveiraC.L.P. NetoA.M.F. PieranskiP. GodinhoM.H. Mind the microgap in iridescent cellulose nanocrystal films.Adv. Mater.2017292160356010.1002/adma.201603560 27862372
     [Google Scholar]
  49. CanejoJ.P. BorgesJ.P. GodinhoM.H. BrogueiraP. TeixeiraP.I.C. TerentjevE.M. Helical twisting of electrospun liquid crystalline cellulose micro-and nanofibers.Adv. Mater.200820244821482510.1002/adma.200801008
     [Google Scholar]
  50. HanF. WangT. LiuG. LiuH. XieX. WeiZ. LiJ. JiangC. HeY. XuF. Materials with tunable optical properties for wearable epidermal sensing in health monitoring.Adv. Mater.20223426210905510.1002/adma.202109055 35258117
     [Google Scholar]
  51. YanZ. LiaoX. HeG. LiS. GuoF. ZouF. LiG. Green and high-expansion PLLA/PDLA foams with excellent thermal insulation and enhanced compressive properties.Ind. Eng. Chem. Res.20205943192441925110.1021/acs.iecr.0c02492
     [Google Scholar]
  52. WuP. WangJ. JiangL. Bio-inspired photonic crystal patterns.Mater. Horiz.20207233836510.1039/C9MH01389J
     [Google Scholar]
  53. WangH. ZhangK.Q. Photonic crystal structures with tunable structure color as colorimetric sensors.Sensors20131344192421310.3390/s130404192 23539027
     [Google Scholar]
  54. GieseM. KhanM.K. HamadW.Y. MacLachlanM.J. Imprinting of photonic patterns with thermosetting amino-formaldehyde-cellulose composites.ACS Macro Lett.20132981882110.1021/mz4003722 35606986
     [Google Scholar]
  55. BardetR. BelgacemN. BrasJ. Flexibility and color monitoring of cellulose nanocrystal iridescent solid films using anionic or neutral polymers.ACS Appl. Mater. Interfaces2015774010401810.1021/am506786t 25552332
     [Google Scholar]
  56. ZhangZ.L. DongX. FanY.N. YangL.M. HeL. SongF. WangX.L. WangY.Z. Chameleon-inspired variable coloration enabled by a highly flexible photonic cellulose film.ACS Appl. Mater. Interfaces20201241467104671810.1021/acsami.0c13551 32965096
     [Google Scholar]
  57. XuM. LiW. MaC. YuH. WuY. WangY. ChenZ. LiJ. LiuS. Multifunctional chiral nematic cellulose nanocrystals/glycerol structural colored nanocomposites for intelligent responsive films, photonic inks and iridescent coatings.J. Mater. Chem. C Mater. Opt. Electron. Devices20186205391540010.1039/C8TC01321G
     [Google Scholar]
  58. ItoT. KatsuraC. SugimotoH. NakanishiE. InomataK. Strain-responsive structural colored elastomers by fixing colloidal crystal assembly.Langmuir20132945139511395710.1021/la4030266 24099483
     [Google Scholar]
  59. BoottC.E. TranA. HamadW.Y. MacLachlanM.J. Cellulose nanocrystal elastomers with reversible visible color.Angew. Chem. Int. Ed.202059122623110.1002/anie.201911468 31663249
     [Google Scholar]
  60. KoseO. BoottC.E. HamadW.Y. MacLachlanM.J. Stimuli-responsive anisotropic materials based on unidirectional organization of cellulose nanocrystals in an elastomer.Macromolecules201952145317532410.1021/acs.macromol.9b00863
     [Google Scholar]
  61. SunC. ZhuD. JiaH. YangC. ZhengZ. WangX. Bio-based visual optical pressure-responsive sensor.Carbohydr. Polym.202126011782311782310.1016/j.carbpol.2021.117823 33712164
     [Google Scholar]
  62. WanH. LiX. ZhangL. LiX. LiuP. JiangZ. YuZ.Z. Rapidly responsive and flexible chiral nematic cellulose nanocrystal composites as multifunctional rewritable photonic papers with eco-friendly inks.ACS Appl. Mater. Interfaces20181065918592510.1021/acsami.7b19375 29363303
     [Google Scholar]
  63. ChenT. ZhaoQ. MengX. LiY. PengH. WhittakerA.K. ZhuS. Ultrasensitive magnetic tuning of optical properties of films of cholesteric cellulose nanocrystals.ACS Nano20201489440944810.1021/acsnano.0c00506 32574040
     [Google Scholar]
  64. SantosM.V. TercjakA. GutierrezJ. BarudH.S. NapoliM. NalinM. RibeiroS.J.L. Optical sensor platform based on cellulose nanocrystals (CNC) – 4′-(hexyloxy)-4-biphenylcarbonitrile (HOBC) bi-phase nematic liquid crystal composite films.Carbohydr. Polym.201716834635510.1016/j.carbpol.2017.03.078 28457459
     [Google Scholar]
  65. TangL. WangL. YangX. FengY. LiY. FengW. Poly(N-isopropylacrylamide)-based smart hydrogels: Design, properties and applications.Prog. Mater. Sci.202111510070210070210.1016/j.pmatsci.2020.100702
     [Google Scholar]
  66. SunC. ZhuD. JiaH. LeiK. ZhengZ. WangX. Humidity and heat dual response cellulose nanocrystals/poly(N -Isopropylacrylamide) composite films with cyclic performance.ACS Appl. Mater. Interfaces20191142391923920010.1021/acsami.9b14201 31564097
     [Google Scholar]
  67. SuiY. LiX. ChangW. WanH. LiW. YangF. YuZ.Z. Multi-responsive nanocomposite membranes of cellulose nanocrystals and poly(N-isopropyl acrylamide) with tunable chiral nematic structures.Carbohydr. Polym.202023211577811577810.1016/j.carbpol.2019.115778 31952587
     [Google Scholar]
  68. BoottC.E. SotoM.A. HamadW.Y. MacLachlanM.J. Shape‐memory photonic thermoplastics from cellulose nanocrystals.Adv. Funct. Mater.20213143210326810.1002/adfm.202103268
     [Google Scholar]
  69. ShanD. GerhardE. ZhangC. TierneyJ.W. XieD. LiuZ. YangJ. Polymeric biomaterials for biophotonic applications.Bioact. Mater.20183443444510.1016/j.bioactmat.2018.07.001 30151431
     [Google Scholar]
  70. LiD. WangL. Cellulose acetate polymer film modified microstructured polymer optical fiber towards a nitrite optical probe.Opt. Commun.2010283142841284410.1016/j.optcom.2010.04.005
     [Google Scholar]
  71. GuimarãesC.F. AhmedR. MarquesA.P. ReisR.L. DemirciU. Engineering hydrogel-based biomedical photonics: Design, fabrication, and applications.Adv. Mater.20213323200658210.1002/adma.202006582 33929771
     [Google Scholar]
  72. WangX. LiQ. GuanY. ZhangY. Glucose oxidase-incorporated hydrogel thin film for fast optical glucose detecting under physiological conditions.Mater. Today Chem.20161-271410.1016/j.mtchem.2016.10.005
     [Google Scholar]
  73. ZhuZ. LiuL. LiuZ. ZhangY. ZhangY. Surface-plasmon-resonance-based optical-fiber temperature sensor with high sensitivity and high figure of merit.Opt. Lett.201742152948295110.1364/OL.42.002948 28957216
     [Google Scholar]
  74. SongS. JungA. HongS. OhK. Strain-insensitive biocompatible temperature sensor based on DNA solid film on an optical microfiber.IEEE Photonics Technol. Lett.201931241925192810.1109/LPT.2019.2950039
     [Google Scholar]
  75. WuW. ShenJ. BanerjeeP. ZhouS. Core–shell hybrid nanogels for integration of optical temperature-sensing, targeted tumor cell imaging, and combined chemo-photothermal treatment.Biomaterials201031297555756610.1016/j.biomaterials.2010.06.030 20643481
     [Google Scholar]
  76. RehmanH.M.M.U. PrasannaA.P.S. RehmanM.M. KhanM. KimS.J. KimW.Y. Edible rice paper-based multifunctional humidity sensor powered by triboelectricity.Sustainable Materials and Technologies202336e0059610.1016/j.susmat.2023.e00596
     [Google Scholar]
  77. LiuZ. LiuW. HuC. ZhangY. YangX. ZhangJ. YangJ. YuanL. Natural spider silk as a photonics component for humidity sensing.Opt. Express20192715219462195510.1364/OE.27.021946 31510261
     [Google Scholar]
  78. HartingsM. DouglassK.O. NeiceC. AhmedZ. Humidity responsive photonic sensor based on a carboxymethyl cellulose mechanical actuator.Sens. Actuators B Chem.201826533533810.1016/j.snb.2018.03.065 31080316
     [Google Scholar]
  79. KhanM. RehmanM.M. KhanS.A. SaqibM. KimW.Y. Characterization and performance evaluation of fully biocompatible gelatin-based humidity sensor for health and environmental monitoring.Front. Mater.202310123313610.3389/fmats.2023.1233136
     [Google Scholar]
  80. ChenR. FengD. ChenG. ChenX. HongW. Re‐printable chiral photonic paper with invisible patterns and tunable wettability.Adv. Funct. Mater.20213116200991610.1002/adfm.202009916
     [Google Scholar]
  81. ChenH. HouA. ZhengC. TangJ. XieK. GaoA. Light- and humidity-responsive chiral nematic photonic crystal films based on cellulose nanocrystals.ACS Appl. Mater. Interfaces20201221245052451110.1021/acsami.0c05139 32362108
     [Google Scholar]
  82. ZhangY.P. ChodavarapuV.P. KirkA.G. AndrewsM.P. Structured color humidity indicator from reversible pitch tuning in self-assembled nanocrystalline cellulose films.Sens. Actuators B Chem.201317669269710.1016/j.snb.2012.09.100
     [Google Scholar]
  83. YaoK. MengQ. BuloneV. ZhouQ. Flexible and responsive chiral nematic cellulose nanocrystal/poly(ethylene glycol) composite films with uniform and tunable structural color.Adv. Mater.20172928170132310.1002/adma.201701323 28558169
     [Google Scholar]
  84. YangH. ChoiS.E. KimD. ParkD. LeeD. ChoiS. NamY.S. KimJ.W. Color-spectrum-broadened ductile cellulose films for vapor-pH-responsive colorimetric sensors.J. Ind. Eng. Chem.20198059059610.1016/j.jiec.2019.08.039
     [Google Scholar]
  85. HouA. ChenH. ZhengC. XieK. GaoA. Assembly of a fluorescent chiral photonic crystal membrane and its sensitive responses to multiple signals induced by small molecules.ACS Nano20201467380738810.1021/acsnano.0c02883 32484339
     [Google Scholar]
  86. SunY. FanW. ZouC. WeiL. LiuJ. XuY. Ternary supramolecular ensembles of cellulose nanocrystals exhibiting multiscale deformation and mechano/chemoresponsive selective reflection of circularly polarized light.ACS Sustain. Chem.& Eng.2019776851685810.1021/acssuschemeng.8b06230
     [Google Scholar]
  87. YuZ. WangK. LuX. Flexible cellulose nanocrystal-based bionanocomposite film as a smart photonic material responsive to humidity.Int. J. Biol. Macromol.202118838539010.1016/j.ijbiomac.2021.08.049 34389384
     [Google Scholar]
  88. BaiL. WangZ. HeY. SongF. WangX. WangY. Flexible photonic cellulose nanocrystal films as a platform with multisensing functions.ACS Sustain. Chem.& Eng.2020850184841849110.1021/acssuschemeng.0c06174
     [Google Scholar]
  89. DaiS. PrempehN. LiuD. FanY. GuM. ChangY. Cholesteric film of Cu(II)-doped cellulose nanocrystals for colorimetric sensing of ammonia gas.Carbohydr. Polym.201717453153910.1016/j.carbpol.2017.06.098 28821101
     [Google Scholar]
/content/journals/cos/10.2174/0115701794279003240124113635
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Recent Progress on Photonic Cellulose Nanocrystal Films for Sensing Applications
Curr. Org. Synth. 22, 198 (2025); https://doi.org/10.2174/0115701794279003240124113635
/content/journals/cos/10.2174/0115701794279003240124113635
/content/journals/cos/10.2174/0115701794279003240124113635
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  • Article Type:     Review Article
Keyword(s): cellulose nanocrystals; cholesteric liquid crystal; film; Nanocellulose; sensing; structural color

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