Department of Applied Physics

Active Matter

The research group focuses on active matter, non-equilibrium systems and fluids and colloids in EM fields.

Current focus

  • Active matter: We investigate behavior of biological micro/milliswimmers in complex environments and interfaces. We also develop, engineer and synthesize artificial systems that mimic naturally occurring active materials.
  • Non-equilibrium systems: Active matter is just one example of non-equilibrium systems. We are interested in the transition between equilibrium and non-equilibrium self-assembly.
  • Fluids and colloids in EM fields: We are interested in the ways that fluids and colloidal matter interact with electric and magnetic fields. We also develop new electromagnetic microtweezing tools for soft matter research.

Open positions

We always welcome applications from enthusiastic researchers of all levels (from students to post-docs). Contact Prof. Jaakko Timonen for details.

Research highlights

  • Daniel D., Timonen J.V.I., Li R., Velling S.J., Aizenberg J.A.,
    Oleoplaning droplets on lubricated surfaces,
    Nature Physics (2017). (link)

  • Timonen J.V.I., Raimondo C., Pilans D., Pillai P.P., Grzybowski B.A.,
    Trapping, Manipulation, and Crystallization of Live Cells Using Magnetofluidic Tweezers,
    Nanoscale Horizons 2, 50-54 (2017). (link)

  • Timonen J.V.I., Demirörs A.F., and Grzybowski B.A., 
    Magnetofluidic Tweezing of Nonmagnetic colloids,
    Advanced Materials 28, 3453-3459 (2016). (link)

  • Timonen J.V.I., Latikka M., Leibler L., Ras R.H.A., and Ikkala O., 
    Switchable Static and Dynamic Self-Assembly of Magnetic Droplets on Superhydrophobic Surfaces,
    Science 341, 253-257 (2013). (link) (press release)

  • Timonen J.V.I., Latikka M., Ikkala O., Ras R.H.A., 
    Free-Decay and Resonant Methods for Investigating the Fundamental Limit of Superhydrophobicity,
    Nature Communications 4, 2398 (2013). (link) (press release)

  • Timonen J.V.I., Seppälä E.T., Ikkala O., and Ras R.H.A., 
    From hot-injection synthesis to heating-up synthesis of cobalt nanoparticles: observation of kinetically controllable nucleation,
    Angewandte Chemie International Edition 50, 2080-2084 (2011). (link)


  • Wet chemistry lab equipped for nanoparticle/colloid synthesis
  • Bioroom equipped for BSL1 micro-organisms
  • Physical measurements lab equipped with
    -  Nikon Ti-E and Zeiss Z1 inverted microscopes
    -  Andor iXon Ultra 888 EMCCD and Zyla 4.2 sCMOS cameras
    -  Photron APX-RS high-speed camera (color, 1024x1024 @ 3000 fps)
    -  Keysight/Keithley precision measurement units and power supplies
  • Other facilities at our disposal
    Nanomicroscopy center (electron microscopy, x-ray scattering) 
    Micronova (nano/microfabrication)
    -  Department of Applied Physics (general tools and equipment)

Latest publications

Compressibility and porosity modulate the mechanical properties of giant gas vesicles

Hedar H. Al-Terke, Grégory Beaune, Muhammad Junaid, Jani Seitsonen, Arja Paananen, Jaakko V.I. Timonen, Jussi Joensuu, Françoise Brochard-Wyart, Robin H.A. Ras 2023 Proceedings of the National Academy of Sciences of the United States of America

Ferrofluidic Manipulator : Theoretical Model for Single-Particle Velocity

Zoran M. Cenev, Ville Havu, Jaakko V.I. Timonen, Quan Zhou 2023 IEEE/ASME Transactions on Mechatronics

In-situ Monitoring of Photocontrollable Wrinkle Erasure in Azobenzene-based Supramolecular Systems

Yujiao Dong, Pedro E.S. Silva, Jaakko V.I. Timonen, Jaana Vapaavuori 2023 ChemPhysChem

Brilliant whiteness in shrimp from ultra-thin layers of birefringent nanospheres

Tali Lemcoff, Lotem Alus, Johannes S. Haataja, Avital Wagner, Gan Zhang, Mariela J. Pavan, Venkata Jayasurya Yallapragada, Silvia Vignolini, Dan Oron, Lukas Schertel, Benjamin A. Palmer 2023 Nature Photonics

Controlling self-assembling co-polymer coatings of hydrophilic polysaccharide substrates via co-polymer block length ratio

Alberto Scacchi, Kourosh Hasheminejad, Sousa Javan Nikkhah, Maria Sammalkorpi 2023 Journal of Colloid and Interface Science

Interactions between Rigid Polyelectrolytes Mediated by Ordering and Orientation of Multivalent Nonspherical Ions in Salt Solutions

Hossein Vahid, Alberto Scacchi, Maria Sammalkorpi, Tapio Ala-Nissila 2023 Physical Review Letters

Theoretical and computational analysis of the electrophoretic polymer mobility inversion induced by charge correlations

Xiang Yang, Sahin Buyukdagli, Alberto Scacchi, Maria Sammalkorpi, Tapio Ala-Nissila 2023 Physical Review E

Functional Magnetic Microdroplets for Antibody Extraction

Hedar H. Al-Terke, Mika Latikka, Jaakko V. I. Timonen, Ladislau Vekas, Arja Paananen, Jussi Joensuu, Robin H. A. Ras 2022 Advanced Materials Interfaces

Dispersing swimming microalgae in self-assembled nanocellulose suspension: Unveiling living colloid dynamics in cholesteric liquid crystals

Guang Chu, Fereshteh Sohrabi, Jaakko V.I. Timonen, Orlando J. Rojas 2022 Journal of Colloid and Interface Science

Recombinant protein condensation inside E. coli enables the development of building blocks for bioinspired materials engineering – Biomimetic spider silk protein as a case study

Bartosz Gabryelczyk, Fred-Eric Sammalisto, Julie-Anne Gandier, Jianhui Feng, Grégory Beaune, Jaakko V.I. Timonen, Markus B. Linder 2022 Materials Today Bio
More information on our research in the Research database.
Research database

Earlier publications (2010 - 2017)

Scientific publications by the Active Matter group pre-2018.

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