Effect of the preparation method on the morphology and proton conductivity of membranes based on sulfonated ABA triblock copolymers
Source abstract
Abstract
Sulfonated ABA triblock copolymers were synthesized based on ionomers with a hydrophilic block such as sulfonated poly(ether ether sulfone) (sPEES) and hydrophobic blocks such as poly(methyl methacrylate) (PMMA) and poly(pentafluorostyrene) (PPFS). The formation of these copolymers was evidenced by Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC) analyses. The copolymers were used to prepare membranes by two approaches: direct self-assembly and infiltration of the polymers into anodized aluminum oxide (AAO) templates. The effect of the copolymer chemical structure (fluorinated and non-fluorinated) and preparation method on the properties of the membranes, such as morphology, thermal stability, water uptake, ion exchange capacity (IEC), and proton conductivity, was evaluated. Both methods used to obtain membranes from ABA copolymers synthesized were successful. Morphological characterization showed that the fluorinated membranes prepared by self-assembly exhibited phase separation. This phase-segregated morphology of partially fluorinated block copolymer structures and high density of sulfonic acid groups had a positive impact on proton exchange capacity and proton conductivity. Moreover, methanol permeability was improved in comparison with Nafion® 117. Otherwise, the morphology of AAO membranes pores filled by infiltration was verified, and the proton conductivity was low due to an increase in the tortuosity which affected proton transport. The present study shows that the membranes prepared by self-assembly of sulfonated ABA block copolymers presented the best properties to be applied as proton exchange membranes.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Fuel Cells and Related Materials · Membrane-based Ion Separation Techniques · Advanced Battery Technologies Research
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (76)
Show source-provided references
1. Nguyen MDT, Dang HS, Kim D (2015) Proton exchange membranes based on sulfonated poly(arylene ether ketone) containing triazole group for enhanced proton conductivity. J Membr Sci 496:13–20. https://doi.org/10.1016/j.memsci.2015.08.02910.1016/j.memsci.2015.08.029 ↗
2. Han H, Liu M, Xu L et al (2015) Construction of proton transport channels on the same polymer chains by covalent crosslinking. J Membr Sci 496:84–94. https://doi.org/10.1016/j.memsci.2015.08.04710.1016/j.memsci.2015.08.047 ↗
3. Wang J, He Y, Zhao L et al (2015) Enhanced proton conductivities of nanofibrous composite membranes enabled by acid-base pairs under hydrated and anhydrous conditions. J Membr Sci 482:1–12. https://doi.org/10.1016/j.memsci.2015.02.01510.1016/j.memsci.2015.02.015 ↗
4. Wang K, Yang L, Wei W et al (2018) Phosphoric acid-doped poly(ether sulfone benzotriazole) for high-temperature proton exchange membrane fuel cell applications. J Membr Sci 549:23–27. https://doi.org/10.1016/j.memsci.2017.11.06710.1016/j.memsci.2017.11.067 ↗
5. Zhang H, Ma C, Wang J et al (2014) Enhancement of proton conductivity of polymer electrolyte membrane enabled by sulfonated nanotubes. Int J Hydrogen Energy 39:974–986. https://doi.org/10.1016/j.ijhydene.2013.10.14510.1016/j.ijhydene.2013.10.145 ↗
6. Yang J, Wang Y, Yang G, Zhan S (2018) New anhydrous proton exchange membranes based on fluoropolymers blend imidazolium poly (aromatic ether ketone)s for high temperature polymer electrolyte fuel cells. Int J Hydrogen Energy 43:8464–8473. https://doi.org/10.1016/j.ijhydene.2018.03.12810.1016/j.ijhydene.2018.03.128 ↗
7. Erdogan T, Bilir C, Unveren EE et al (2015) Novel multiarm star block copolymer ionomers as proton conductive membranes. Polym Chem 6:561–572. https://doi.org/10.1039/c4py00994k10.1039/C4PY00994K ↗
8. He G, Chang C, Xu M et al (2015) Tunable nanochannels along graphene oxide/polymer core-shell nanosheets to enhance proton conductivity. Adv Funct Mater 25:7502–7511. https://doi.org/10.1002/adfm.20150322910.1002/adfm.201503229 ↗
9. Yan XH, Jiang HR, Zhao G et al (2016) Preparations of an inorganic-framework proton exchange nanochannel membrane. J Power Sources 326:466–475. https://doi.org/10.1016/j.jpowsour.2016.07.02210.1016/j.jpowsour.2016.07.022 ↗
10. He Q, Xu T, Qian H et al (2015) Enhanced proton conductivity of sulfonated poly(p-phenylene-co-aryl ether ketone) proton exchange membranes with controlled microblock structure. J Power Sources 278:590–598. https://doi.org/10.1016/j.jpowsour.2014.12.13510.1016/j.jpowsour.2014.12.135 ↗
11. Gloukhovski R, Freger V, Tsur Y (2016) A novel composite nafion/anodized aluminium oxide proton exchange membrane. Fuel Cells 16:434–443. https://doi.org/10.1002/fuce.20150016610.1002/fuce.201500166 ↗
12. Jang J-H, Oleksandrov S, Lee Y-K, Chung C-H (2007) Fabrication of nano-templated proton-exchange electrolyte membrane for fuel cell application. ECS Trans 11:65–6910.1149/1.2780915 ↗
13. Bakangura E, Wu L, Ge L et al (2016) Mixed matrix proton exchange membranes for fuel cells: state of the art and perspectives. Prog Polym Sci 57:103–152. https://doi.org/10.1016/j.progpolymsci.2015.11.00410.1016/j.progpolymsci.2015.11.004 ↗
14. Kim DJ, Jo MJ, Nam SY (2015) A review of polymer-nanocomposite electrolyte membranes for fuel cell application. J Ind Eng Chem 21:36–52. https://doi.org/10.1016/j.jiec.2014.04.03010.1016/j.jiec.2014.04.030 ↗
15. Raghav S (2005) Polymer-filled nanoporous membranes. Drexel University, Philadelphia
16. Bocchetta P, Conciauro F, Di Quarto F (2007) Nanoscale membrane electrode assemblies based on porous anodic alumina for hydrogen–oxygen fuel cell. J Solid State Electrochem 11:1253–1261. https://doi.org/10.1007/s10008-007-0280-x10.1007/s10008-007-0280-x ↗
17. Rayon E, Gonzalez V, Matveeva E, Parkhutik V (2006) Pore filling membrane based on porous anodic alumina and nafion. In: Porous semiconductors science and technology conference PSST-2006, Spain
18. Agudelo NA, Elsen AM, He H et al (2015) ABA triblock copolymers from two mechanistic techniques: polycondensation and atom transfer radical polymerization. J Polym Sci, Part A: Polym Chem 53:228–238. https://doi.org/10.1002/pola.2730010.1002/pola.27300 ↗
19. Agudelo NA, Palacio J, López BL (2016) Sulfonation of poly(arylene ethers) and ABA triblock copolymers with a mild sulfonation agent. Macromol Symp 365:67–80. https://doi.org/10.1002/masy.20165001810.1002/masy.201650018 ↗
20. Liu X, He S, Shi Z et al (2015) Effect of residual casting solvent content on the structure and properties of sulfonated poly (ether ether ketone) membranes effect of residual casting solvent content on the structure and properties of sulfonated poly (ether ether ketone) membranes. J Membr Sci 492:48–57. https://doi.org/10.1016/j.memsci.2015.05.03810.1016/j.memsci.2015.05.038 ↗
21. Guan R, Dai H, Li C et al (2006) Effect of casting solvent on the morphology and performance of sulfonated polyethersulfone membranes. J Membr Sci 277:148–156. https://doi.org/10.1016/j.memsci.2005.10.02510.1016/j.memsci.2005.10.025 ↗
22. Arigonda M, Deshpande AP, Varughese S (2013) Effect of PES on the morphology and properties of proton conducting blends with sulfonated poly(ether ether ketone). J Appl Polym Sci 127:5100–5110. https://doi.org/10.1002/app.3762810.1002/app.37628 ↗
23. Shin CK, Maier G, Andreaus B, Scherer GG (2004) Block copolymer ionomers for ion conductive membranes. J Membr Sci 245:147–161. https://doi.org/10.1016/j.memsci.2004.07.02710.1016/j.memsci.2004.07.027 ↗
24. Roy A, Yu X, Dunn S, McGrath JE (2009) Influence of microstructure and chemical composition on proton exchange membrane properties of sulfonated-fluorinated, hydrophilic–hydrophobic multiblock copolymers. J Membr Sci 327:118–124. https://doi.org/10.1016/j.memsci.2008.11.01610.1016/j.memsci.2008.11.016 ↗
25. Müller F, Ferreira CA, Azambuja DS et al (2014) Measuring the proton conductivity of ion-exchange membranes using electrochemical impedance spectroscopy and through-plane cell. J Phys Chem B 118:1102–1112. https://doi.org/10.1021/jp409675z10.1021/jp409675z ↗
26. Zaidi SM, Mikhailenko S, Robertson G et al (2000) Proton conducting composite membranes from polyether ether ketone and heteropolyacids for fuel cell applications. J Membr Sci 173:17–34. https://doi.org/10.1016/S0376-7388(00)00345-810.1016/S0376-7388(00)00345-8 ↗
27. Jeon JD, Kwak SY (2008) Nafion/sulfated β-cyclodextrin composite membranes for direct methanol fuel cells. J Power Sources 185:49–54. https://doi.org/10.1016/j.jpowsour.2008.06.09310.1016/j.jpowsour.2008.06.093 ↗
28. Kim DJ, Lee HJ, Nam SY (2013) Sulfonated poly(arylene ether sulfone) membranes blended with hydrophobic polymers for direct methanol fuel cell applications. Int J Hydrogen Energy 39:17524–17532. https://doi.org/10.1016/j.ijhydene.2013.09.03010.1016/j.ijhydene.2013.09.030 ↗
29. Kang MS, Choi YJ, Choi IJ et al (2003) Electrochemical characterization of sulfonated poly(arylene ether sulfone) (S-PES) cation-exchange membranes. J Membr Sci 216:39–53. https://doi.org/10.1016/S0376-7388(03)00045-010.1016/S0376-7388(03)00045-0 ↗
30. Zhao Y, Yin J (2010) Synthesis and properties of poly(ether ether ketone)-block-sulfonated polybutadiene copolymers for PEM applications. Eur Polym J 46:592–601. https://doi.org/10.1016/j.eurpolymj.2009.11.00710.1016/j.eurpolymj.2009.11.007 ↗
31. Lu Q, Yang Z, Li X, Jin S (2009) Synthesis, morphology, and melting behavior of poly(ether ether ketone) of different molecular weights. J Appl Polym Sci 114:2060–2070. https://doi.org/10.1002/app10.1002/app.30786 ↗
32. Huth F, Govyadinov A, Amarie S et al (2012) Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution. Nano Lett 12:3973–3978. https://doi.org/10.1021/nl301159v10.1021/nl301159v ↗
33. Liu Y, Hu W, Lua Z, Li CM (2010) Photografted poly (methyl methacrylate)-based high performance protein microarray for hepatitis B virus biomarker detection in human serum. Med Chem Commun 1:132–13510.1039/c0md00032a ↗
34. Wlassics I, Tortelli V, Carella S et al (2011) Perfluoro allyl fluorosulfate (FAFS): a versatile building block for new fluoroallylic compounds. Molecules 16:6512–6540. https://doi.org/10.3390/molecules1608651210.3390/molecules16086512 ↗
35. Li H, Rathi S, Sterner ES et al (2013) Synthesis of photocleavable poly(methyl methacrylate-block-d-lactide) via atom-transfer radical polymerization and ring-opening polymerization. J Polym Sci, Part A: Polym Chem 51:4309–4316. https://doi.org/10.1002/pola.2684010.1002/pola.26840 ↗
36. Taskin OS, Temel BA, Tasdelen MA, Yagci Y (2015) Synthesis of block copolymers by selective H-abstraction and radical coupling reactions using benzophenone/benzhydrol photoinitiating system. Eur Polym J 62:304–311. https://doi.org/10.1016/j.eurpolymj.2014.07.00710.1016/j.eurpolymj.2014.07.007 ↗
37. Verma H, Kannan T (2008) Synthesis of tri-block copolymers through reverse atom transfer radical polymerization of methyl methacrylate using polyurethane macroiniferter. eXPRESS Polym Lett 2:579–588. https://doi.org/10.3144/expresspolymlett.2008.7010.3144/expresspolymlett.2008.70 ↗
38. Orhan T, Ates S, Hacaloglu J, Yagci Y (2012) Thermal degradation characteristics of polysulfones with benzoxazine end groups. J Anal Appl Pyrolysis 94:146–152. https://doi.org/10.1016/j.jaap.2011.12.00110.1016/j.jaap.2011.12.001 ↗
39. Fu BG, Yuan Z, Kang E et al (2005) Nanoporous ultra-low-dielectric-constant fluoropolymer films via selective UV decomposition of poly (pentafluorostyrene)—block-poly (methyl methacrylate) copolymers prepared using atom transfer. Radic Polym 15:315–322. https://doi.org/10.1002/adfm.20040013810.1002/adfm.200400138 ↗
40. Ferriol M, Gentilhomme A, Cochez M et al (2003) Thermal degradation of poly (methyl methacrylate)(PMMA): modelling of DTG and TG curves. Polym Degrad Stab 79:271–281. https://doi.org/10.1016/S0141-3910(02)00291-410.1016/S0141-3910(02)00291-4 ↗
41. Lou L, Koike Y, Okamoto Y (2010) Synthesis and properties of copolymers of methyl methacrylate with 2,3,4,5,6-pentafluoro and 4-trifluoromethyl 2,3,5,6-tetrafluoro styrenes: an intrachain interaction between methyl ester and fluoro aromatic moieties. J Polym Sci, Part A: Polym Chem 48:4938–4942. https://doi.org/10.1002/pola.2428810.1002/pola.24288 ↗
42. Guan R, Zou H, Lu D et al (2005) Polyethersulfone sulfonated by chlorosulfonic acid and its membrane characteristics. Eur Polym J 41:1554–1560. https://doi.org/10.1016/j.eurpolymj.2005.01.01810.1016/j.eurpolymj.2005.01.018 ↗
43. Unveren EE, Erdogan T, Elebi SSC, Inan TY (2010) Role of post-sulfonation of poly (ether ether sulfone) in proton conductivity and chemical stability of its proton exchange membranes for fuel cell. Int J Hydrogen Energy 35:3736–3744. https://doi.org/10.1016/j.ijhydene.2010.01.04110.1016/j.ijhydene.2010.01.041 ↗
44. Carbone A, Pedicini R, Portale G et al (2006) Sulphonated poly (ether ether ketone) membranes for fuel cell application: Thermal and structural characterisation. J Power Sources 163:18–26. https://doi.org/10.1016/j.jpowsour.2005.12.06610.1016/j.jpowsour.2005.12.066 ↗
45. Liu X, He S, Song G et al (2016) Proton conductivity improvement of sulfonated poly(ether ether ketone) nanocomposite membranes with sulfonated halloysite nanotubes prepared via dopamine-initiated atom transfer radical polymerization. J Membr Sci 504:206–219. https://doi.org/10.1016/j.memsci.2016.01.02310.1016/j.memsci.2016.01.023 ↗
46. Oh K, Ketpang K, Kim H, Shanmugam S (2016) Synthesis of sulfonated poly(arylene ether ketone) block copolymers for proton exchange membrane fuel cells. J Membr Sci 507:135–142. https://doi.org/10.1016/j.memsci.2016.02.02710.1016/j.memsci.2016.02.027 ↗
47. Li N, Lee SY, Liu Y-L et al (2012) A new class of highly-conducting polymer electrolyte membranes: aromatic ABA triblock copolymers. Energy Environ Sci 5:5346–5355. https://doi.org/10.1039/C1EE02556B10.1039/C1EE02556B ↗
48. Liu Z, Bai Y, Sun D et al (2015) Preparation and performance of sulfonated polysulfone flat ultrafiltration membranes. Polym Eng Sci 55:1003–1011. https://doi.org/10.1002/pen10.1002/pen.23968 ↗
49. Parnian MJ, Rowshanzamir S, Gashoul F (2017) Comprehensive investigation of physicochemical and electrochemical properties of sulfonated poly (ether ether ketone) membranes with different degrees of sulfonation for proton exchange membrane fuel cell applications. Energy 125:614–628. https://doi.org/10.1016/j.energy.2017.02.14310.1016/j.energy.2017.02.143 ↗
50. Badami AS, Mcgrath JE, Davis RM, et al (2007) Morphological and structure-property analyses of poly(arylene ether sulfone)—based random and multiblock copolymers for fuel cells. Ph.D. Thesis, Macromolecular Science and Engineering, Blacksburg, VA
51. Choi JH, Willis CL, Winey KI (2012) Structure-property relationship in sulfonated pentablock copolymers. J Membr Sci 394–395:169–174. https://doi.org/10.1016/j.memsci.2011.12.03610.1016/j.memsci.2011.12.036 ↗
52. Tsang EMW, Shi Z, Holdcroft S (2011) Ionic purity and connectivity of proton-conducting channels in fluorous-ionic diblock copolymers. Macromolecules 44:8845–8857. https://doi.org/10.1021/ma201046910.1021/ma2010469 ↗
53. Mohanty AK, Mistri EA, Banerjee S et al (2013) Highly fluorinated sulfonated poly (arylene ether sulfone) copolymers: synthesis and evaluation of proton exchange membrane properties. Ind Eng Chem Res 52:2772–2783. https://doi.org/10.1021/ie303380a10.1021/ie303380a ↗
54. Hur J, Bae J (2015) Solvent induced conversion of microdomain structure in block copolymer electrolyte thin films. J Ind Eng Chem 21:851–855. https://doi.org/10.1016/j.jiec.2014.04.02210.1016/j.jiec.2014.04.022 ↗
55. Choi JH, Kota A, Winey KI (2010) Micellar morphology in sulfonated pentablock copolymer solutions. Ind Eng Chem Res 49:12093–12097. https://doi.org/10.1021/ie100247610.1021/ie1002476 ↗
56. Maranesi B, Hou H, Polini R et al (2013) Cross-linking of sulfonated poly(ether ether ketone) by thermal treatment: how does the reaction occur? Fuel Cells 13:107–117. https://doi.org/10.1002/fuce.20120001010.1002/fuce.201200010 ↗
57. Zeng Y, Wang Z, Wan L et al (2003) Surface morphology and nodule formation mechanism of cellulose acetate membranes by atomic force microscopy. J Appl Polym Sci 88:1328–1335. https://doi.org/10.1002/app.1183310.1002/app.11833 ↗
58. Gloukhovski R, Freger V, Tsur Y (2017) Understanding methods of preparation and characterization of pore-filling polymer composites for proton exchange membranes: a beginner’s guide. Rev Chem Eng. https://doi.org/10.1515/revce-2016-006510.1515/revce-2016-0065 ↗
59. Kumar V, Kumar P, Nandy A, Kundu PP (2015) Crosslinked inter penetrating network of sulfonated styrene and sulfonated PVdF-co-HFP as electrolytic membrane in a single chamber microbial fuel cell. RSC Adv 5:30758–30767. https://doi.org/10.1039/b000000x10.1039/C5RA03411F ↗
60. Muthumeenal A, Neelakandan S, Kanagaraj P, Nagendran A (2016) Synthesis and properties of novel proton exchange membranes based on sulfonated polyethersulfone and N-phthaloyl chitosan blends for DMFC applications. Renew Energy 86:922–929. https://doi.org/10.1016/j.renene.2015.09.01810.1016/j.renene.2015.09.018 ↗
61. Date B, Han J, Park S et al (2018) Synthesis and morphology study of SEBS triblock copolymers functionalized with sulfonate and phosphonate groups for proton exchange membrane fuel cells. Macromolecules 51:1020–1030. https://doi.org/10.1021/acs.macromol.7b0184810.1021/acs.macromol.7b01848 ↗
62. Sannigrahi A, Takamuku S, Jannasch P (2014) Block copolymers combining semi-fluorinated poly(arylene ether) and sulfonated poly(arylene ether sulfone) segments for proton exchange membranes. Int J Hydrogen Energy 39:15718–15727. https://doi.org/10.1016/j.ijhydene.2014.07.15510.1016/j.ijhydene.2014.07.155 ↗
63. Kang K, Kim D (2015) Comparison of proton conducting polymer electrolyte membranes prepared from multi-block and random copolymers based on poly(arylene ether ketone). J Power Sources 281:146–157. https://doi.org/10.1016/j.jpowsour.2015.01.17710.1016/j.jpowsour.2015.01.177 ↗
64. Kim YS, Einsla B, Sankir M et al (2006) Structure-property-performance relationships of sulfonated poly(arylene ether sulfone)s as a polymer electrolyte for fuel cell applications. Polymer 47:4026–4035. https://doi.org/10.1016/j.polymer.2006.02.03210.1016/j.polymer.2006.02.032 ↗
65. Miyake J, Watanabe M, Miyatake K (2014) Ammonium-functionalized poly (arylene ether)s as anion-exchange membranes. Polym J 46:656–663. https://doi.org/10.1038/pj.2014.5610.1038/pj.2014.56 ↗
66. Moore HD, Saito T, Hickner MA (2010) Morphology and transport properties of midblock-sulfonated triblock copolymers. J Mater Chem 20:6316–6321. https://doi.org/10.1039/c0jm00068j10.1039/c0jm00068j ↗
67. Kim B, Kannan R, Nahm KS, Yoo DJ (2016) Development and characterization of highly conducting nonfluorinated di and triblock copolymers for polymer electrolyte membranes. J Dispers Sci Technol 37:1315–132310.1080/01932691.2015.1092090 ↗
68. Xu K, Li K, Khanchaitit P, Wang Q (2007) Synthesis and characterization of self-assembled sulfonated poly(styrene-b-vinylidene fluoride-b-styrene) triblock copolymers for proton conductive membranes. Chem Mater 19:5937–5945. https://doi.org/10.1021/cm071626s10.1021/cm071626s ↗
69. Pérez-Pérez M, Suleiman D (2016) Effect of block composition on the morphology, hydration, and transport properties of sulfonated PS-b-PEGPEM-b-PS. J Appl Polym Sci 44343:1–12. https://doi.org/10.1002/app.4434310.1002/app.44343 ↗
70. Elabd YA, Hickner MA (2011) Block copolymers for fuel cells. Macromolecules 44:1–11. https://doi.org/10.1021/ma101247c10.1021/ma101247c ↗
71. Oleksandrov S, Lee J, Jang J et al (2009) Proton-conductive nanochannel membrane for fuel-cell applications. J Nanosci Nanotechnol 9:1551–1554. https://doi.org/10.1166/jnn.2009.C20010.1166/jnn.2009.C200 ↗
72. Harrison WL, Hickner MA, Kim YS, McGrath JE (2005) Poly(arylene ether sulfone) copolymers and related systems from disulfonated monomer building blocks: synthesis, characterization, and performance—atopical review. Fuel Cells 5:201–212. https://doi.org/10.1002/fuce.20040008410.1002/fuce.200400084 ↗
73. Kim AR, Vinothkannan M, Yoo DJ (2017) Artificially designed, low humidifying organic–inorganic (SFBC-50/FSiO2) composite membrane for electrolyte applications of fuel cells. Compos Part B 130:103–118. https://doi.org/10.1016/j.compositesb.2017.07.04210.1016/j.compositesb.2017.07.042 ↗
74. Kim AR, Vinothkannan M, Yoo DJ (2018) Sulfonated fluorinated multi-block copolymer hybrid containing sulfonated(poly ether ether ketone) and graphene oxide: a ternary hybrid membrane architecture for electrolyte applications in proton exchange membrane fuel cells. J Energy Chem 27:1247–1260. https://doi.org/10.1016/j.jechem.2018.02.02010.1016/j.jechem.2018.02.020 ↗
75. Dutta K, Das S, Kundu PP (2014) Low methanol permeable and highly selective membranes composed of pure and/or partially sulfonated PVdF-co-HFP and polyaniline. J Membr Sci 468:42–51. https://doi.org/10.1016/j.memsci.2014.05.04910.1016/j.memsci.2014.05.049 ↗
76. Dutta K, Das S, Kumar P, Kundu PP (2014) Polymer electrolyte membrane with high selectivity ratio for direct methanol fuel cells: a preliminary study based on blends of partially sulfonated polymers polyaniline and PVdF-co-HFP. Appl Energy 118:183–191. https://doi.org/10.1016/j.apenergy.2013.12.02910.1016/j.apenergy.2013.12.029 ↗