Improved PNIPAAm-Hydrogel Photopatterning by Process Optimisation with Respect to UV Light Sources and Oxygen Content
1
Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universität Dresden, 01062 Dresden, Germany
2
Physical Chemistry of Polymers, Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062 Dresden, Germany
3
Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062 Dresden, Germany
*
Author to whom correspondence should be addressed.
Academic Editor: Dirk Kuckling
Gels 2016, 2(1), 10; https://doi.org/10.3390/gels2010010
Received: 25 January 2016 / Revised: 16 February 2016 / Accepted: 18 February 2016 / Published: 4 March 2016
(This article belongs to the Special Issue Stimuli-Responsive Gels)
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.
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Keywords:
photopatterning; photopolymerisation; PNIPAAm; stimuli-responsive hydrogel; reproducibility
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MDPI and ACS Style
Haefner, S.; Rohn, M.; Frank, P.; Paschew, G.; Elstner, M.; Richter, A. Improved PNIPAAm-Hydrogel Photopatterning by Process Optimisation with Respect to UV Light Sources and Oxygen Content. Gels 2016, 2, 10.
AMA Style
Haefner S, Rohn M, Frank P, Paschew G, Elstner M, Richter A. Improved PNIPAAm-Hydrogel Photopatterning by Process Optimisation with Respect to UV Light Sources and Oxygen Content. Gels. 2016; 2(1):10.
Chicago/Turabian StyleHaefner, Sebastian; Rohn, Mathias; Frank, Philipp; Paschew, Georgi; Elstner, Martin; Richter, Andreas. 2016. "Improved PNIPAAm-Hydrogel Photopatterning by Process Optimisation with Respect to UV Light Sources and Oxygen Content" Gels 2, no. 1: 10.
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