{"title":"含有非热塑性共聚单体的 NIPAM 基共聚物微凝胶的体积相变","authors":"Jannis Krüger, Sergej Kakorin, Thomas Hellweg","doi":"10.1007/s00396-024-05288-1","DOIUrl":null,"url":null,"abstract":"<p>We analyze the swelling behavior of <i>N</i>-isopropylacrylamide (NIPAM)-based microgels incorporating the non-thermoresponsive comonomer <i>N</i>-<i>tert</i>-butylacrylamide (NtBAM) using photon correlation spectroscopy (PCS) and atomic force microscopy (AFM). Previous thermodynamic analysis of PNIPAM-co-NtBAM microgel swelling relied on the classical Flory-Rehner theory. However, this approach struggled to accurately describe swelling curves at higher NtBAM content. Our present work combines the original expression for the Flory-Huggins interaction parameter <span>\\(\\chi _{FH}\\)</span> for NtBAM with a recently adapted Hill-like model for the interaction parameter <span>\\(\\chi _{Hill}\\)</span> that accounts for cooperative effects in the volume phase transition in poly(NIPAM) microgels. This approach outperforms other methods in fitting quality. The observed results are revealing an exponential decrease in hydrodynamic radius upon increasing NtBAM content for swollen microgels. In addition, an exponential decay of the number of water molecules leaving the polymer chain during the volume phase transition is found, which can be attributed to the steric influence of one NtBAM monomer on the hydration of neighboring NIPAM monomers. The molar interaction enthalpy <span>\\(\\Delta H_{SP}= \\text {-49 kJ / mol}\\)</span> and entropy <span>\\(\\Delta S_{SP} = \\text {-177 J /( mol K)}\\)</span> were obtained from the fits of the swelling curves.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\n","PeriodicalId":520,"journal":{"name":"Colloid and Polymer Science","volume":null,"pages":null},"PeriodicalIF":2.2000,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Volume phase transition of NIPAM based copolymer microgels with non-thermoresponsive comonomers\",\"authors\":\"Jannis Krüger, Sergej Kakorin, Thomas Hellweg\",\"doi\":\"10.1007/s00396-024-05288-1\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We analyze the swelling behavior of <i>N</i>-isopropylacrylamide (NIPAM)-based microgels incorporating the non-thermoresponsive comonomer <i>N</i>-<i>tert</i>-butylacrylamide (NtBAM) using photon correlation spectroscopy (PCS) and atomic force microscopy (AFM). Previous thermodynamic analysis of PNIPAM-co-NtBAM microgel swelling relied on the classical Flory-Rehner theory. However, this approach struggled to accurately describe swelling curves at higher NtBAM content. Our present work combines the original expression for the Flory-Huggins interaction parameter <span>\\\\(\\\\chi _{FH}\\\\)</span> for NtBAM with a recently adapted Hill-like model for the interaction parameter <span>\\\\(\\\\chi _{Hill}\\\\)</span> that accounts for cooperative effects in the volume phase transition in poly(NIPAM) microgels. This approach outperforms other methods in fitting quality. The observed results are revealing an exponential decrease in hydrodynamic radius upon increasing NtBAM content for swollen microgels. In addition, an exponential decay of the number of water molecules leaving the polymer chain during the volume phase transition is found, which can be attributed to the steric influence of one NtBAM monomer on the hydration of neighboring NIPAM monomers. The molar interaction enthalpy <span>\\\\(\\\\Delta H_{SP}= \\\\text {-49 kJ / mol}\\\\)</span> and entropy <span>\\\\(\\\\Delta S_{SP} = \\\\text {-177 J /( mol K)}\\\\)</span> were obtained from the fits of the swelling curves.</p><h3 data-test=\\\"abstract-sub-heading\\\">Graphical Abstract</h3>\\n\",\"PeriodicalId\":520,\"journal\":{\"name\":\"Colloid and Polymer Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.2000,\"publicationDate\":\"2024-07-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Colloid and Polymer Science\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1007/s00396-024-05288-1\",\"RegionNum\":4,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Colloid and Polymer Science","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1007/s00396-024-05288-1","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Volume phase transition of NIPAM based copolymer microgels with non-thermoresponsive comonomers
We analyze the swelling behavior of N-isopropylacrylamide (NIPAM)-based microgels incorporating the non-thermoresponsive comonomer N-tert-butylacrylamide (NtBAM) using photon correlation spectroscopy (PCS) and atomic force microscopy (AFM). Previous thermodynamic analysis of PNIPAM-co-NtBAM microgel swelling relied on the classical Flory-Rehner theory. However, this approach struggled to accurately describe swelling curves at higher NtBAM content. Our present work combines the original expression for the Flory-Huggins interaction parameter \(\chi _{FH}\) for NtBAM with a recently adapted Hill-like model for the interaction parameter \(\chi _{Hill}\) that accounts for cooperative effects in the volume phase transition in poly(NIPAM) microgels. This approach outperforms other methods in fitting quality. The observed results are revealing an exponential decrease in hydrodynamic radius upon increasing NtBAM content for swollen microgels. In addition, an exponential decay of the number of water molecules leaving the polymer chain during the volume phase transition is found, which can be attributed to the steric influence of one NtBAM monomer on the hydration of neighboring NIPAM monomers. The molar interaction enthalpy \(\Delta H_{SP}= \text {-49 kJ / mol}\) and entropy \(\Delta S_{SP} = \text {-177 J /( mol K)}\) were obtained from the fits of the swelling curves.
期刊介绍:
Colloid and Polymer Science - a leading international journal of longstanding tradition - is devoted to colloid and polymer science and its interdisciplinary interactions. As such, it responds to a demand which has lost none of its actuality as revealed in the trends of contemporary materials science.