The search result changed since you submitted your search request. Documents might be displayed in a different sort order.
  • search hit 50 of 56560
Back to Result List

Hydration and Dehydration Kinetics: Comparison between Poly(N-isopropyl methacrylamide) and Poly(methoxy diethylene glycol acrylate) Films

  • Thermoresponsive films of poly(N-isopropyl methacrylamide) (PNIPMAM) and poly(methoxy diethylene glycol acrylate) (PMDEGA) are compared with respect to their hydration and dehydration kinetics using in situ neutron reflectivity. Both as-prepared films present a homogeneous single-layer structure and have similar transition temperatures of the lower critical solution temperature type (TT, PNIPMAM 38 degrees C and PMDEGA 41 degrees C). After hydration in unsaturated D2O vapor at 23 degrees C, a D2O enrichment layer is observed in PNIPMAM films adjacent to the Si substrate. In contrast, two enrichment layers are present in PMDEGA films (close to the vapor interface and the Si substrate). PNIPMAM films exhibit a higher hydration capability, ascribed to having both donor (N-H) and acceptor (C=O) units for hydrogen bonds. "While the swelling of the PMDEGA films is mainly caused by the increase of the enrichment layers, the thickness of the entire PNIPMAM films increases with time. The observed longer relaxation time for swelling of PNIPMAMThermoresponsive films of poly(N-isopropyl methacrylamide) (PNIPMAM) and poly(methoxy diethylene glycol acrylate) (PMDEGA) are compared with respect to their hydration and dehydration kinetics using in situ neutron reflectivity. Both as-prepared films present a homogeneous single-layer structure and have similar transition temperatures of the lower critical solution temperature type (TT, PNIPMAM 38 degrees C and PMDEGA 41 degrees C). After hydration in unsaturated D2O vapor at 23 degrees C, a D2O enrichment layer is observed in PNIPMAM films adjacent to the Si substrate. In contrast, two enrichment layers are present in PMDEGA films (close to the vapor interface and the Si substrate). PNIPMAM films exhibit a higher hydration capability, ascribed to having both donor (N-H) and acceptor (C=O) units for hydrogen bonds. "While the swelling of the PMDEGA films is mainly caused by the increase of the enrichment layers, the thickness of the entire PNIPMAM films increases with time. The observed longer relaxation time for swelling of PNIPMAM films is attributed to the much higher glass transition temperature of PNIPMAM. When dehydrating both films by increasing the temperature above the TT, they react with a complex response consisting of three stages (shrinkage, rearrangement, and reswelling). PNIPMAM films respond faster than PMDEGA films. After dehydration, both films still contain a large amount of D2O, and no completely dry film state is reached for a temperature above their TTs.show moreshow less

Export metadata

Additional Services

Search Google Scholar Statistics
Metadaten
Author details:Sophie Nieuwenhuis, Qi ZhongORCiD, Ezzeldin MetwalliORCiD, Lorenz Biessmann, Martine PhilippORCiD, Anna Miasnikova, Andre LaschewskyORCiDGND, Christine M. PapadakisORCiDGND, Robert Cubitt, Jiping Wang, Peter Müller-BuschbaumORCiD
DOI:https://doi.org/10.1021/acs.langmuir.9b00535
ISSN:0743-7463
Pubmed ID:https://pubmed.ncbi.nlm.nih.gov/31117727
Title of parent work (English):Langmuir
Publisher:American Chemical Society
Place of publishing:Washington
Publication type:Article
Language:English
Date of first publication:2019/06/18
Publication year:2019
Release date:2021/01/20
Volume:35
Issue:24
Number of pages:12
First page:7691
Last Page:7702
Funding institution:DFG priority program "Intelligente Hydrogele" [Mu1487/8, Pa771/4, La611/7]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China [51403186, 51611130312]; Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education MinistryScientific Research Foundation for the Returned Overseas Chinese Scholars
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie
DDC classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Peer review:Referiert
Accept ✔
This website uses technically necessary session cookies. By continuing to use the website, you agree to this. You can find our privacy policy here.