{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:18:42Z","timestamp":1760242722717,"version":"build-2065373602"},"reference-count":25,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2016,3,4]],"date-time":"2016-03-04T00:00:00Z","timestamp":1457049600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Research Training Group 1865 Hydrogel-Based Microsystems"},{"name":"Center for Advancing Electronics Dresden"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>Poly-N-isopropylacrylamide (PNIPAAm) hydrogels, known for their sensor and actuator capabilities, can be photolithographically structured for microsystem applications. For usage in microsystems, the preparation, and hence the characteristics, of these hydrogels (e.g., degree of swelling, size, cooperative diffusion coefficient) are key features, and have to be as reproducible as possible. A common method of hydrogel fabrication is free radical polymerisation using a thermally-initiated system or a photoinitiator system. Due to the reaction quenching by oxygen, the polymer solution has to be rinsed with protective inert gases like nitrogen or argon before the polymerisation process. In this paper, we focus on the preparation reproducibility of PNIPAAm hydrogels under different conditions, and investigate the influence of oxygen and the UV light source during the photopolymerisation process. The flushing of the polymer solution with inert gas is not sufficient for photostructuring approaches, so a glove box preparation resulting in better quality. Moreover, the usage of a wide-band UV light source yields higher reproducibility to the photostructuring process compared to a narrow-band UV source.<\/jats:p>","DOI":"10.3390\/gels2010010","type":"journal-article","created":{"date-parts":[[2016,3,4]],"date-time":"2016-03-04T10:53:34Z","timestamp":1457088814000},"page":"10","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Improved PNIPAAm-Hydrogel Photopatterning by Process Optimisation with Respect to UV Light Sources and Oxygen Content"],"prefix":"10.3390","volume":"2","author":[{"given":"Sebastian","family":"Haefner","sequence":"first","affiliation":[{"name":"Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universit\u00e4t Dresden, 01062 Dresden, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mathias","family":"Rohn","sequence":"additional","affiliation":[{"name":"Physical Chemistry of Polymers, Department of Chemistry and Food Chemistry, Technische Universit\u00e4t Dresden, 01062 Dresden, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Philipp","family":"Frank","sequence":"additional","affiliation":[{"name":"Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universit\u00e4t Dresden, 01062 Dresden, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Georgi","family":"Paschew","sequence":"additional","affiliation":[{"name":"Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universit\u00e4t Dresden, 01062 Dresden, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Martin","family":"Elstner","sequence":"additional","affiliation":[{"name":"Center for Advancing Electronics Dresden (cfaed), Technische Universit\u00e4t Dresden, 01062 Dresden, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andreas","family":"Richter","sequence":"additional","affiliation":[{"name":"Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universit\u00e4t Dresden, 01062 Dresden, Germany"},{"name":"Center for Advancing Electronics Dresden (cfaed), Technische Universit\u00e4t Dresden, 01062 Dresden, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,3,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2826","DOI":"10.1016\/j.biomaterials.2009.01.040","article-title":"Silk fibroin\/polyacrylamide semi-interpenetrating network hydrogels for controlled drug release","volume":"30","author":"Mandal","year":"2009","journal-title":"Biomaterials"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.addr.2012.09.010","article-title":"Hydrogels for biomedical applications","volume":"64","author":"Hoffman","year":"2012","journal-title":"Adv. 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