Fabrication of flexible hydrogel sheets featuring periodically spaced circular holes with continuously adjustable size in realtime
- We report on the formation of stimuli-responsive structured hydrogel thin films whose pattern geometry can be adjusted on demand and tuned reversibly by varying solvent quality or by changing temperature. The hydrogel films, similar to 100 nm in thickness, were prepared by depositing layers of random copolymers comprising N-isopropylacrylamide and ultraviolet (UV)-active methacryloyloxybenzophenone units onto solid substrates. A two-beam interference pattern technique was used to cross-link the selected areas of the film; any unreacted material was extracted using ethanol after UV light-assisted cross-linking. In this way, we produced nanoholes, perfectly ordered structures with a narrow size distribution, negligible tortuosity, adjustable periodicity, and a high density. The diameter of the circular holes ranged from a few micrometers down to several tens of nanometers; the hole periodicity could be adjusted readily by changing the optical period of the UV interference pattern. The holes were reversibly closed and opened byWe report on the formation of stimuli-responsive structured hydrogel thin films whose pattern geometry can be adjusted on demand and tuned reversibly by varying solvent quality or by changing temperature. The hydrogel films, similar to 100 nm in thickness, were prepared by depositing layers of random copolymers comprising N-isopropylacrylamide and ultraviolet (UV)-active methacryloyloxybenzophenone units onto solid substrates. A two-beam interference pattern technique was used to cross-link the selected areas of the film; any unreacted material was extracted using ethanol after UV light-assisted cross-linking. In this way, we produced nanoholes, perfectly ordered structures with a narrow size distribution, negligible tortuosity, adjustable periodicity, and a high density. The diameter of the circular holes ranged from a few micrometers down to several tens of nanometers; the hole periodicity could be adjusted readily by changing the optical period of the UV interference pattern. The holes were reversibly closed and opened by swelling/deswelling the polymer networks in the presence of ethanol and water, respectively, at various temperatures. The reversible regulation of the hole diameter can be repeated many times within a few seconds. The hydrogel sheet with circular holes periodically arranged may also be transferred onto different substrates and be employed as tunable templates for the deposition of desired substances.…
Author details: | Joachim JelkenORCiDGND, Chinnayan Kannan PandiyarajanORCiDGND, Jan GenzerORCiDGND, Nino Lomadze, Svetlana SanterORCiDGND |
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DOI: | https://doi.org/10.1021/acsami.8b09580 |
ISSN: | 1944-8244 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/30114362 |
Title of parent work (English): | ACS applied materials & interfaces |
Publisher: | American Chemical Society |
Place of publishing: | Washington |
Publication type: | Article |
Language: | English |
Date of first publication: | 2018/09/12 |
Publication year: | 2018 |
Release date: | 2021/10/04 |
Tag: | PNIPAm; UV cross-linking; azobenzene-containing molecules; hydrogels; photosensitive polymers; stimuli-responsive structured polymer films |
Volume: | 10 |
Issue: | 36 |
Number of pages: | 8 |
First page: | 30844 |
Last Page: | 30851 |
Funding institution: | Helmholtz Graduate School on Macromolecular Bioscience (Teltow, Germany); National Science FoundationNational Science Foundation (NSF) [DMR 1809453] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik | |
Peer review: | Referiert |