title: A chaotic self-oscillating sunlight-driven polymer actuator.
abstract: Nature provides much inspiration for the design of materials capable of motion upon exposure to external stimuli, and many examples of such active systems have been created in the laboratory. However, to achieve continuous motion driven by an unchanging, constant stimulus has proven extremely challenging. Here we describe a liquid crystalline polymer film doped with a visible light responsive fluorinated azobenzene capable of continuous chaotic oscillatory motion when exposed to ambient sunlight in air. The presence of simultaneous illumination by blue and green light is necessary for the oscillating behaviour to occur, suggesting that the dynamics of continuous forward and backward switching are causing the observed effect. Our work constitutes an important step towards the realization of autonomous, persistently self-propelling machines and self-cleaning surfaces powered by sunlight.
authors.affiliation: Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Kumar
authors.affiliation: Department of Chemistry and IRIS Adlershof, Humboldt-Universitat zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Knie
authors.affiliation: Department of Chemistry and IRIS Adlershof, Humboldt-Universitat zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Bléger
authors.affiliation: Department of Mathematics and Computer Science, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.|Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Peletier
authors.affiliation: Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Heiner
authors.initials: H
authors.lastname: Friedrich
authors.affiliation: Department of Chemistry and IRIS Adlershof, Humboldt-Universitat zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hecht
authors.affiliation: Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.|Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Broer
authors.affiliation: Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Debije
authors.affiliation: Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.|Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Albertus P H J
authors.initials: AP
authors.lastname: Schenning