{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T15:56:49Z","timestamp":1791302209685,"version":"4.1.0"},"reference-count":39,"publisher":"American Chemical Society (ACS)","issue":"39","license":[{"start":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T00:00:00Z","timestamp":1790294400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100007288","name":"Mahasarakham University","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100007288","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Achieving complete stereocomplex (SC) formation in high-molecular-weight PLLA\/PDLA blends by injection molding remains a challenge because the rapid mold-cooling rate suppresses the slow enantiomeric chain-recognition process. Here, we demonstrate that the PEG middle-block molecular weight in PLLA\u2013PEG\u2013PLLA triblock copolymers is the decisive kinetic control variable governing SC formation efficiency (fSC). Copolymers with PEG Mn = 400, 4000, and 35,000 g\/mol were synthesized by bulk ring-opening polymerization (ROP) at two PLLA-block Mn targets (100,000 and 200,000 g\/mol) and blended 1:1 with PDLA before injection molding. WPLA-corrected differential scanning calorimetry (DSC) showed that fSC increased monotonically from approximately 75\u201376% (PEG400) to 93\u201395% (PEG4k) and to 100% (PEG35k), where the value was confirmed independently by X-ray diffraction (XRD). PEG35k-containing SC specimens crystallized completely during mold cooling without any postcooling cold crystallization, establishing Mn,PEG \u2265 35,000 g\/mol as the practical threshold for complete in-mold stereocomplex at Mn \u2248 200,000 g\/mol without postprocessing annealing. Toughness increased 7.1-fold, from 10.1 MJ m\u20133 (neat PLLA) to 71.5 MJ m\u20133 (L100 K-35k-L100 K\/PDLA), driven by synergistic PEG-induced ductility and SC crystal reinforcement. All SC\u2013PLLA-PEG-PLLA specimens maintained dimensional stability at 200 \u00b0C, whereas non-SC counterparts melted.<\/jats:p>","DOI":"10.1021\/acsomega.6c08171","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T22:02:28Z","timestamp":1790373748000},"page":"60350-60359","source":"Crossref","is-referenced-by-count":0,"title":["PEG Middle-Block\nMolecular Weight as a Quantitative\nDesign Variable for Stereocomplex Formation Efficiency in High-Molecular-Weight\nPLLA\u2013PEG\u2013PLLA\/PDLA Blends"],"prefix":"10.1021","volume":"11","author":[{"given":"Dutchanee","family":"Pholharn","sequence":"first","affiliation":[{"name":"Rajabhat Mahasarakham University , , ,","place":["Mahasarakham, Thailand, 44000"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samaneh","family":"Dehghani","sequence":"additional","affiliation":[{"name":"Kunsan National University , , ,","place":["Gunsan, Republic of Korea, 54150"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Onpreeya","family":"Veang-in","sequence":"additional","affiliation":[{"name":"Rajamangala University of Technology Isan , , ,","place":["Sakon Nakhon, Thailand, 47160"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7288-8219","authenticated-orcid":true,"given":"Yottha","family":"Srithep","sequence":"additional","affiliation":[{"name":"Mahasarakham University , , ,","place":["Mahasarakham, Thailand, 44150"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,25]]},"reference":[{"key":"2026100610493103200_cit1","doi-asserted-by":"publisher","first-page":"835","DOI":"10.1002\/mabi.200400043","article-title":"An overview of polylactides as packaging\nmaterials","volume":"4","author":"Auras","year":"2004","journal-title":"Macromol. 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Sci."},{"key":"2026100610493103200_cit5","doi-asserted-by":"publisher","first-page":"1657","DOI":"10.1016\/j.progpolymsci.2012.07.005","article-title":"Poly (lactic acid)\ncrystallization","volume":"37","author":"Saeidlou","year":"2012","journal-title":"Prog. Polym. Sci."},{"key":"2026100610493103200_cit6","doi-asserted-by":"publisher","first-page":"820","DOI":"10.1016\/j.progpolymsci.2008.05.004","article-title":"Processing\ntechnologies for poly\n(lactic acid)","volume":"33","author":"Lim","year":"2008","journal-title":"Prog. Polym. 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Biosci."},{"key":"2026100610493103200_cit13","doi-asserted-by":"publisher","first-page":"5449","DOI":"10.1016\/j.polymer.2012.09.043","article-title":"Stereocomplex formation of high-molecular-weight\npolylactide: A low temperature approach","volume":"53","author":"Bao","year":"2012","journal-title":"Polymer"},{"key":"2026100610493103200_cit14","doi-asserted-by":"publisher","first-page":"128919","DOI":"10.1016\/j.ijbiomac.2023.128919","article-title":"Remarkably enhanced stereocomplex\ncrystallization of high-molar-mass\nenantiomeric polylactide blends by adding double-grafted copolymers","volume":"258","author":"Yuan","year":"2024","journal-title":"Int. J. Biol. Macromol."},{"key":"2026100610493103200_cit15","doi-asserted-by":"publisher","first-page":"6820","DOI":"10.1002\/pen.70714","article-title":"Molecular Weight\u2013Dependent\nStereocomplex Crystallization, Thermal Stability, and Mechanical Performance\nof PLLA\/PDLA Blends Plasticized With Epoxidized Soybean Oil: Experimental\nCharacterization and Finite Element Validation","volume":"66","author":"Li","year":"2026","journal-title":"Polym. Eng. Sci."},{"key":"2026100610493103200_cit16","doi-asserted-by":"publisher","first-page":"347","DOI":"10.1021\/ma402405c","article-title":"Stereocomplex\nformation in enantiomeric polylactides by melting recrystallization\nof homocrystals: crystallization kinetics and crystal morphology","volume":"47","author":"Na","year":"2014","journal-title":"Macromolecules"},{"key":"2026100610493103200_cit17","doi-asserted-by":"publisher","first-page":"5651","DOI":"10.1021\/acs.macromol.4c02836","article-title":"Formation of PLA stereocomplex crystals\nthrough homorecrystallization and mesophase growth mechanisms","volume":"58","author":"Ahmadi","year":"2025","journal-title":"Macromolecules"},{"key":"2026100610493103200_cit18","doi-asserted-by":"publisher","first-page":"1137","DOI":"10.1021\/ma902536p","article-title":"Stereocomplex formation\nof high-molecular-weight polylactide\nusing supercritical fluid","volume":"43","author":"Purnama","year":"2010","journal-title":"Macromolecules"},{"key":"2026100610493103200_cit19","doi-asserted-by":"publisher","first-page":"6462","DOI":"10.1021\/acs.jpcb.5b03546","article-title":"Competitive\nstereocomplexation, homocrystallization, and polymorphic crystalline\ntransition in poly (L-lactic acid)\/poly (D-lactic acid) racemic blends:\nmolecular weight effects","volume":"119","author":"Pan","year":"2015","journal-title":"J. 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Polym. Mater."},{"key":"2026100610493103200_cit30","doi-asserted-by":"publisher","first-page":"2129","DOI":"10.3390\/polym16152129","article-title":"The effect of polyethylene glycol\non the non-isothermal\ncrystallization of poly (L-lactide) and poly (D-lactide) blends","volume":"16","author":"Phuangthong","year":"2024","journal-title":"Polymers"},{"key":"2026100610493103200_cit31","doi-asserted-by":"publisher","first-page":"10","DOI":"10.1016\/j.polymdegradstab.2014.01.023","article-title":"Improved Mechanical\nand Thermal Properties of PLLA by Solvent Blending\nwith PDLA-b-PEG-b-PDLA","volume":"101","author":"Liu","year":"2014","journal-title":"Polym. Degrad. Stab."},{"key":"2026100610493103200_cit32","doi-asserted-by":"publisher","first-page":"18850","DOI":"10.1021\/acs.iecr.5c02825","article-title":"Crystalline\nStructure And Physical Properties Of Heat-Resistant Poly (Lactic Acid)\nBy Injection Molding Within The Melting Range Of Preformed Stereocomplex\nCrystals","volume":"64","author":"Yan","year":"2025","journal-title":"Ind. Eng. Chem. Res."},{"key":"2026100610493103200_cit33","doi-asserted-by":"publisher","first-page":"723","DOI":"10.1002\/polb.1989.090270401","article-title":"Chain structure\nand entanglement","volume":"27","author":"Wu","year":"1989","journal-title":"J. Polym. Sci., Part B: Polym.\nPhys."},{"key":"2026100610493103200_cit34","doi-asserted-by":"publisher","first-page":"1000","DOI":"10.1021\/acs.jchemed.1c00824","article-title":"Synthesis\nof a biodegradable PLA:\nNMR signal deconvolution and end-group analysis","volume":"99","author":"Perez","year":"2022","journal-title":"J. Chem. Educ."},{"key":"2026100610493103200_cit35","doi-asserted-by":"publisher","first-page":"6147","DOI":"10.1016\/S0032-3861(98)00822-2","article-title":"Synthesis and characterization\nof poly (ethylene glycol)\/poly\n(L-lactic acid) alternating multiblock copolymers","volume":"40","author":"Huh","year":"1999","journal-title":"Polymer"},{"key":"2026100610493103200_cit36","doi-asserted-by":"publisher","first-page":"607","DOI":"10.1122\/1.1896957","article-title":"Melt rheology\nof variable L-content poly (lactic acid)","volume":"49","author":"Dorgan","year":"2005","journal-title":"J.\nRheol."},{"key":"2026100610493103200_cit37","doi-asserted-by":"publisher","first-page":"4114","DOI":"10.1021\/ma00042a011","article-title":"Stereocomplex formation\nbetween enantiomeric poly (lactic\nacid) s. 7. Phase structure of the stereocomplex crystallized from\na dilute acetonitrile solution as studied by high-resolution solid-state\ncarbon-13 NMR spectroscopy","volume":"25","author":"Tsuji","year":"1992","journal-title":"Macromolecules"},{"key":"2026100610493103200_cit38","doi-asserted-by":"publisher","first-page":"3316","DOI":"10.1021\/bm060786e","article-title":"Electrospinning of\npoly (lactic acid)\nstereocomplex nanofibers","volume":"7","author":"Tsuji","year":"2006","journal-title":"Biomacromolecules"},{"key":"2026100610493103200_cit39","doi-asserted-by":"publisher","first-page":"1851","DOI":"10.3390\/polym13111851","article-title":"Relationship between the stereocomplex crystallization\nbehavior and mechanical properties of PLLA\/PDLA blends","volume":"13","author":"Park","year":"2021","journal-title":"Polymers"}],"container-title":["ACS Omega"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acsomega.6c08171","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/acsodf\/article-pdf\/11\/39\/60350\/68664205\/acsomega.6c08171.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/acsodf\/article-pdf\/11\/39\/60350\/68664205\/acsomega.6c08171.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T15:18:39Z","timestamp":1791299919000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/acsodf\/article\/11\/39\/60350\/5439203\/PEG-Middle-Block-Molecular-Weight-as-a"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,25]]},"references-count":39,"journal-issue":{"issue":"39","published-online":{"date-parts":[[2026,9,25]]},"published-print":{"date-parts":[[2026,10,6]]}},"URL":"https:\/\/doi.org\/10.1021\/acsomega.6c08171","relation":{},"ISSN":["2470-1343"],"issn-type":[{"value":"2470-1343","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,25]]}}}