INS13-0257
From molecular actuation to microscopic motion
Topic
S13. Korea-Germany Polymer Symposium 2026: “Pioneering the Future of Polymeric Materials and Bridging Innovation in Sustainable Technologies”
When and Where
Sep 29, 2026
15:25 - 15:50
Room 203
Session Chairs
Jürgen Rühe
Presenter(s)
Svetlana Santer (University of Potsdam, Institute of Physics and Astronomy, Karl-Liebcknecht Str. 24)
Co-Author(s)
Abstract
Azobenzene molecules can be considered as molecular actuators that convert optical energy in mechanical work. In this talk I will show several interesting examples where azobenzene can be used in order to actuate matter on large time and length scales. In all these examples the azobenzene plays the role of a transducer that mediates between different states of size, shape, position and interfacial energy of several nano-scale soft materials.
In the first part of my talk I will show how using a home made set-up combining an atomic force microscope (AFM) and two-beam interferometry it is possible to address two major points concerning the experimental efforts in understanding surface relief grating (SRG) formation in azobenzene containing polymers: (i) how is the orientation of the electric field vector within the interfering electromagnetic fields related to the topographical pattern within the SRG; (ii) how can one measure locally the opto-mechanical forces emerging during topography change. We will discuss three distinct systems: polymer films, polymer brushes, and azobenzene containing polymer nanoparticles. [1-4]
In the second part of my talk I will show how, using azobenzene containing surfactant, [5] one can manipulate microparticles and even induce their self-propulsion when trapped at a solid/liquid interface. Depending on the applied wave length one can either disperse/remove or gather particles. The physical origin of this genuine behaviour is related to the phenomenon of light driven diffusioosmosis (LDDO). [6,7] During irradiation of a solution containing azobenzene surfactants with focused light, there is a formation of local flow at the solid/liquid interface. The corresponding hydrodynamic forces are sufficiently strong to swiftly clean the illuminated area from particles trapped at the interface. When the colloids are made into Janus particles, their self-propulsion can be initiated in the solution of azobenzene containing surfactant even under global/homogeneous illumination with blue light. We will discuss how to establish light-driven hydrodynamics as a useful and versatile tool for investigating collective motion of self-propelled particles and aggregation. At the very end of my talk I will present further examples of azo-induced actuation of soft matter. Microgel particles made light sensitive with azo-surfactants can change their volume (growing or shrinking) by up to a factor of 8 and LCST point between 32°C and 85°C in response to illumination with two different wavelengths. [8, 9]
References
[1] Jelken, J.; Santer, S. RSC Advances, 9 (2019) 20295.
[2] Di Florio, G.; Brundermann, E.; Yadavalli, N.S.; Santer, S.A.; Havenith, M. Nano Letters, 14 (2014) 5754.
[3] Loebner, S.; Lomadze, N.; Kopyshev, A.; Koch, M.; Guskova, O.; Grenzer Saphiannikova, M.; Santer, S. A. J. Phys. Chem. B, 122 (2018) 2001.
[4] Lomadze, N.; Kopyshev, A.; Bargheer, M.; Wollgarten, M.; Santer, S. Scientific Reports, 7 (2017) 8506.
[5] Santer, S. J. Phys. D: Applied Physics, 51 (2017) 013002.
[6] Feldmann, D.; Maduar S.R.; Santer, M.; Lomadze, N.; Vinogradova O.I.; Santer, S. Scientific Reports, 6 (2016) 36443.
[7] Arya, P.; Umlandt, M.; Jelken, J.; Feldmann, D.; Lomadze, N.; Asmolov , E. S.; Vinogradova, O. I.; Santer, S. A. The European Physical Journal E, 44(50) (2021), 1-10.
[8] Schimka, S.; Gordievskaya, Y.D.; Lomadze, N.; Lehmann, M.; von Klitzing, R.; Rumyantsev, A.M.; Kramarenko, E.; Santer, S. J. Chem. Phys., 147 (2017) 031101.
[9] Jelken J.; Jung S.; Lomadze N.; Gordievskaya Y. D.; Kramarenko E. Y.; Pich A.; Santer S. Adv. Funct. Mater., (2021), 2107946.
In the first part of my talk I will show how using a home made set-up combining an atomic force microscope (AFM) and two-beam interferometry it is possible to address two major points concerning the experimental efforts in understanding surface relief grating (SRG) formation in azobenzene containing polymers: (i) how is the orientation of the electric field vector within the interfering electromagnetic fields related to the topographical pattern within the SRG; (ii) how can one measure locally the opto-mechanical forces emerging during topography change. We will discuss three distinct systems: polymer films, polymer brushes, and azobenzene containing polymer nanoparticles. [1-4]
In the second part of my talk I will show how, using azobenzene containing surfactant, [5] one can manipulate microparticles and even induce their self-propulsion when trapped at a solid/liquid interface. Depending on the applied wave length one can either disperse/remove or gather particles. The physical origin of this genuine behaviour is related to the phenomenon of light driven diffusioosmosis (LDDO). [6,7] During irradiation of a solution containing azobenzene surfactants with focused light, there is a formation of local flow at the solid/liquid interface. The corresponding hydrodynamic forces are sufficiently strong to swiftly clean the illuminated area from particles trapped at the interface. When the colloids are made into Janus particles, their self-propulsion can be initiated in the solution of azobenzene containing surfactant even under global/homogeneous illumination with blue light. We will discuss how to establish light-driven hydrodynamics as a useful and versatile tool for investigating collective motion of self-propelled particles and aggregation. At the very end of my talk I will present further examples of azo-induced actuation of soft matter. Microgel particles made light sensitive with azo-surfactants can change their volume (growing or shrinking) by up to a factor of 8 and LCST point between 32°C and 85°C in response to illumination with two different wavelengths. [8, 9]
References
[1] Jelken, J.; Santer, S. RSC Advances, 9 (2019) 20295.
[2] Di Florio, G.; Brundermann, E.; Yadavalli, N.S.; Santer, S.A.; Havenith, M. Nano Letters, 14 (2014) 5754.
[3] Loebner, S.; Lomadze, N.; Kopyshev, A.; Koch, M.; Guskova, O.; Grenzer Saphiannikova, M.; Santer, S. A. J. Phys. Chem. B, 122 (2018) 2001.
[4] Lomadze, N.; Kopyshev, A.; Bargheer, M.; Wollgarten, M.; Santer, S. Scientific Reports, 7 (2017) 8506.
[5] Santer, S. J. Phys. D: Applied Physics, 51 (2017) 013002.
[6] Feldmann, D.; Maduar S.R.; Santer, M.; Lomadze, N.; Vinogradova O.I.; Santer, S. Scientific Reports, 6 (2016) 36443.
[7] Arya, P.; Umlandt, M.; Jelken, J.; Feldmann, D.; Lomadze, N.; Asmolov , E. S.; Vinogradova, O. I.; Santer, S. A. The European Physical Journal E, 44(50) (2021), 1-10.
[8] Schimka, S.; Gordievskaya, Y.D.; Lomadze, N.; Lehmann, M.; von Klitzing, R.; Rumyantsev, A.M.; Kramarenko, E.; Santer, S. J. Chem. Phys., 147 (2017) 031101.
[9] Jelken J.; Jung S.; Lomadze N.; Gordievskaya Y. D.; Kramarenko E. Y.; Pich A.; Santer S. Adv. Funct. Mater., (2021), 2107946.
