{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,5]],"date-time":"2026-07-05T01:19:05Z","timestamp":1783214345360,"version":"3.54.6"},"reference-count":27,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2014,12,2]],"date-time":"2014-12-02T00:00:00Z","timestamp":1417478400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>In this paper we examine the suitability of SU-8 2000 as a construction material for electrothermal actuators and the actuator stability for long-term operation. The fabrication of SU-8 was optimized for mechanical and thermal stability. Samples with different softbake duration, exposure dose and postbake temperature were evaluated using Fourier-Transform IR-spectroscopy and dynamic-mechanical analysis. The exposure dose and postbake temperature proved to have a strong influence on the cross-linking and the glass transition temperature. A final hardbake levels the effects of the process history. A high degree of crosslinking, a low drop of the dynamic modulus over temperature (30%) up to the glass transition temperature 100\u2013140 \u00b0C were achieved for SU-8 with an exposure dose of 1500 mJ\/cm\u00b2, a postbake temperature of 95 \u00b0C and hardbake of 240 \u00b0C. Electrothermal actuators proved to be stable until the end of the experiment after 2400 duty cycles. Actuator deflections up to 55 \u03bcm were measured (actuator length: 4 mm) for input powers up to 160 mW and a maximum operating temperature of 120 \u00b0C. Higher temperatures led to permanent deformations and failure. An offset drift of up to 20% occurs during actuation, but converges after a burn-in phase of about two hours.<\/jats:p>","DOI":"10.3390\/mi5041310","type":"journal-article","created":{"date-parts":[[2014,12,2]],"date-time":"2014-12-02T10:57:54Z","timestamp":1417517874000},"page":"1310-1322","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["SU-8 Electrothermal Actuators: Optimization of Fabrication and Excitation for Long-Term Use"],"prefix":"10.3390","volume":"5","author":[{"given":"Thomas","family":"Winterstein","sequence":"first","affiliation":[{"name":"Microtechnology and Electromechanical Systems Laboratory, Institute of Electromechanical Design, Technische Universit\u00e4t Darmstadt, Merckstr. 25, 64283 Darmstadt, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthias","family":"Staab","sequence":"additional","affiliation":[{"name":"Microtechnology and Electromechanical Systems Laboratory, Institute of Electromechanical Design, Technische Universit\u00e4t Darmstadt, Merckstr. 25, 64283 Darmstadt, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Nakic","sequence":"additional","affiliation":[{"name":"Microtechnology and Electromechanical Systems Laboratory, Institute of Electromechanical Design, Technische Universit\u00e4t Darmstadt, Merckstr. 25, 64283 Darmstadt, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hans-J\u00fcrgen","family":"Feige","sequence":"additional","affiliation":[{"name":"Laboratory of Experimental Solid and Micro Mechanics, Faculty of Automotive Engineering, Wests\u00e4chsische Hochschule Zwickau, Dr.-Friedrichs-Ring 2A, 08056 Zwickau, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J\u00fcrgen","family":"Vogel","sequence":"additional","affiliation":[{"name":"Laboratory of Experimental Solid and Micro Mechanics, Faculty of Automotive Engineering, Wests\u00e4chsische Hochschule Zwickau, Dr.-Friedrichs-Ring 2A, 08056 Zwickau, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helmut","family":"Schlaak","sequence":"additional","affiliation":[{"name":"Microtechnology and Electromechanical Systems Laboratory, Institute of Electromechanical Design, Technische Universit\u00e4t Darmstadt, Merckstr. 25, 64283 Darmstadt, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2014,12,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1007\/s00542-009-0939-6","article-title":"A sub-micron metallic electrothermal gripper","volume":"16","author":"Park","year":"2010","journal-title":"Microsyst. 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