{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T22:21:18Z","timestamp":1790893278351,"version":"4.1.0"},"reference-count":45,"publisher":"National Academy of Sciences","issue":"38","license":[{"start":{"date-parts":[[2025,9,16]],"date-time":"2025-09-16T00:00:00Z","timestamp":1757980800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"NSF","doi-asserted-by":"publisher","award":["No. CMMI-1925790"],"award-info":[{"award-number":["No. CMMI-1925790"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000001","name":"NSF","doi-asserted-by":"publisher","award":["No. CMMI-2403592"],"award-info":[{"award-number":["No. CMMI-2403592"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2025,9,23]]},"abstract":"<jats:p>Liquid crystal elastomers (LCEs) are anisotropic, viscoelastic materials integrating polymer networks and liquid crystals. While their mechanical responses have been extensively studied, their fracture behavior remains largely unexplored. Specifically, the effect of the deformation-director coupling on LCE fracture paths is unknown, and fracture criteria for LCEs are not yet established. To address this gap, we combine experimental and theoretical approaches to investigate fracture propagation in LCEs. We stretch edge-cracked monodomain LCE samples, recording their stress-stretch responses and crack paths under varying initial directors and stretching rates. Our findings reveal that cracks can change direction during propagation, which are highly dependent on both the initial director and the stretching rate. To further understand LCE fracture behavior, we develop a rate-dependent phase-field fracture model, which is validated through experiments, and demonstrates the ability to predict complex fracture paths. Our study paves the way for designing LCEs with enhanced fracture properties, imperative for their future applications.<\/jats:p>","DOI":"10.1073\/pnas.2510727122","type":"journal-article","created":{"date-parts":[[2025,9,16]],"date-time":"2025-09-16T17:55:08Z","timestamp":1758045308000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":5,"title":["Fracture of liquid crystal elastomers"],"prefix":"10.1073","volume":"122","author":[{"given":"Yu","family":"Zhou","sequence":"first","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of California Los Angeles","place":["Los Angeles"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chen","family":"Wei","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of California Los Angeles","place":["Los Angeles"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7812-9056","authenticated-orcid":false,"given":"Lihua","family":"Jin","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of California Los Angeles","place":["Los Angeles"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2025,9,16]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1039\/C8CS00595H"},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1002\/adma.201901924"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1080\/14686996.2018.1549460"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1002\/adfm.201805924"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1002\/adem.201700016"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1002\/admt.201800477"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201800907"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41578-018-0022-y"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev-conmatphys-042020-023937"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1088\/0034-4885\/79\/4\/046601"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1820424116"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-021-24835-w"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.compstruct.2013.05.039"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.1126\/sciadv.abc0496"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1039\/D4SM00042K"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2105974118"},{"key":"e_1_3_4_17_2","volume-title":"Liquid Crystal Elastomers","author":"Warner M.","year":"2007","unstructured":"M. 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Terentjev, Liquid Crystal Elastomers (Oxford University Press, 2007), vol. 120."},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1039\/D3SM00770G"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijsolstr.2024.112712"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmps.2022.104829"},{"key":"e_1_3_4_21_2","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevE.78.041704"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmps.2019.02.018"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.eml.2020.100936"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmps.2023.105522"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1142\/S1758825116400019"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.engfracmech.2022.108584"},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1039\/D4SM01042F"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijmecsci.2020.105941"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmps.2025.106027"},{"key":"e_1_3_4_30_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmps.2017.03.015"},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1016\/bs.aams.2019.08.001"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1002\/nme.2861"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.eml.2022.101944"},{"key":"e_1_3_4_34_2","doi-asserted-by":"publisher","DOI":"10.1007\/s10704-023-00700-3"},{"key":"e_1_3_4_35_2","article-title":"Synthesis of programmable main-chain liquid-crystalline elastomers using a two-stage thiol-acrylate reaction","volume":"107","author":"Saed M. O.","year":"2016","unstructured":"M. O. Saed, A. H. Torbati, D. P. Nair, C. M. Yakacki, Synthesis of programmable main-chain liquid-crystalline elastomers using a two-stage thiol-acrylate reaction. J. Vis. Exp. 107, 53546 (2016).","journal-title":"J. Vis. Exp."},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cma.2018.10.044"},{"key":"e_1_3_4_37_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.crme.2015.11.004"},{"key":"e_1_3_4_38_2","doi-asserted-by":"crossref","unstructured":"F. Kamarei E. Breedlove O. Lopez-Pamies Nucleation and propagation of fracture in viscoelastic elastomers: A complete phase-field theory. arXiv [Preprint] (2025). https:\/\/doi.org\/10.48550\/arXiv.2506.16479 (Accessed 19 June 2025).","DOI":"10.2139\/ssrn.5312721"},{"key":"e_1_3_4_39_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.engfracmech.2024.109878"},{"key":"e_1_3_4_40_2","article-title":"Quantifying rate-and temperature-dependent molecular damage in elastomer fracture","volume":"10","author":"Slootman J.","year":"2020","unstructured":"J. Slootman , Quantifying rate-and temperature-dependent molecular damage in elastomer fracture. Phys. Rev. X 10, 041045 (2020).","journal-title":"Phys. Rev. X"},{"key":"e_1_3_4_41_2","article-title":"Real-time early detection of crack propagation precursors in delayed fracture of soft elastomers","volume":"13","author":"Ju J.","year":"2023","unstructured":"J. Ju , Real-time early detection of crack propagation precursors in delayed fracture of soft elastomers. Phys. Rev. X 13, 021030 (2023).","journal-title":"Phys. Rev. X"},{"key":"e_1_3_4_42_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp9906482"},{"key":"e_1_3_4_43_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.engfracmech.2021.108089"},{"key":"e_1_3_4_44_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.engfracmech.2022.108872"},{"key":"e_1_3_4_45_2","unstructured":"L. Jin Data depository for \u201cFracture of liquid crystal elastomers.\u201d Github. https:\/\/github.com\/LihuaJinMSM\/LCE_fracture. Deposited 29 August 2025."}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.2510727122","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.2510727122","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,9,16]],"date-time":"2025-09-16T17:55:40Z","timestamp":1758045340000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/10.1073\/pnas.2510727122"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,16]]},"references-count":45,"journal-issue":{"issue":"38","published-print":{"date-parts":[[2025,9,23]]}},"alternative-id":["10.1073\/pnas.2510727122"],"URL":"https:\/\/doi.org\/10.1073\/pnas.2510727122","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,9,16]]},"assertion":[{"value":"2025-05-01","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-08-18","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-09-16","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e2510727122"}}