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Research Zernike (ZIAM) Micromechanics Onck Group

Bio-inspired, smart, responsive materials

This work aims at understanding and designing bio-inspired, smart and responsive materials by developing computational models (molecular dynamics, solid-fluid interaction techniques and finite-element models) for application in, e.g., NEMS/MEMS, microfluidic systems and lab-on-chip applications. Emphasis is on magneto-, electro- and photomechanical interactions.

1. Switchable surface topographies by photo-responsive liquid crystal coatings

We use azobenzene-modified liquid-crystal polymers to design coatings that can be switched by light. We focus on different surface topographies and analyze the underlying physical mechanisms by using continuum modelling to describe the light attenuation process and the internal stress distributions that are key in generating the patterns. We study micro-domain, linearly patterned and fingerprint coatings, the effect of dual wavelength light and we generate surface waves by rotating a polarized light source.

Switchable surface topographies by photo-responsive liquid crystal coatings
Switchable surface topographies by photo-responsive liquid crystal coatings

PhD student: L.Liu. In collaboration with D.J. Broer (Eindhoven University of Technology) and R.K. Annabattula (IIT Madras).

Publications

  • Mehta, K., Peeketi, A. R., Sol, J. A. H. P., Debije, M. G., Onck, P.R., Annabattula, R. K. (2020). Modeling of surface waves in photo-responsive viscoelastic liquid crystal thin films under a moving light source. Mechanics of Materials 147, [103388]. DOI: 10.1016/j.mechmat.2020.103388
  • Liu, L., Broer, D. J., & Onck, P. R. (2019). Travelling waves on photo-switchable patterned liquid crystal polymer films directed by rotating polarized light. Soft Matter, 15(40), 8040-8050. DOI: /10.1039/c9sm01594a
  • Liu, L., & Onck, P. R. (2019). Light-driven topographical morphing of azobenzene-doped liquid crystal polymer films via tunable photo-polymerization induced diffusion. Journal of the Mechanics and Physics of Solids, 123, 247-266. DOI: 10.1016/j.jmps.2018.09.021
  • Liu, L., & Onck, P. R. (2018). Topographical changes in photo-responsive liquid crystal films: a computational analysis. Soft Matter. DOI: 10.1039/c7sm02474f
  • Liu, L., & Onck, P. R. (2017). Enhanced Deformation of Azobenzene-Modified Liquid Crystal Polymers under Dual Wavelength Exposure: A Photophysical Model. Physical Review Letters , 119(5), [057801]. DOI: 10.1103/PhysRevLett.119.057801
  • Liu*, D., Liu*, L., Onck, P. R., & Broer, D. J. (2015). Reverse switching of surface roughness in a self-organized polydomain liquid crystal coating. PNAS 112(13), 3880-3885. DOI: 10.1073/pnas.1419312112, *contributed equally to this work.

2. Digital microfluidics: droplet transport on switchable surfaces

Digital microfluidics: droplet transport on switchable surfaces
Digital microfluidics: droplet transport on switchable surfaces

In digital-microfluidic systems, discrete droplets containing biofluids or particles are used as small reactors, and transporting droplets with full control over their contents is an essential property of such systems. Here we show that surface topographies made from switchable materials are able to transport droplets through dynamic pinning forces. The transport performance was demonstrated in both 2D and 3D and its dependence on the fluid and structural parameters was numerically investigated by means of a two-phase computational fluid dynamics model.

PhD student: E. de Jong. In collaboration with J. den Toonder (Eindhoven University of Technology).

Publications

3. Bio-inspired, artificial cilia and flagella

Snapshot of a computational fluid dynamics simulation of magnetically-actuated artificial cilia, generating fluid flow in a microfluidic channel.
Snapshot of a computational fluid dynamics simulation of magnetically-actuated artificial cilia, generating fluid flow in a microfluidic channel.

Cilia and flagella are long hair-like projections from the surface of living cells that play an important role in cell motility. Cells and micro-organisms use cilia and flagella to propel themselves or to propel the fluid surrounding them. Here we use the natural beating pattern as inspiration to design bio-inspired cilia and flagella. We use polymeric films embedded by magnetic nanoparticles that are actuated by applying a rotating or oscillating magnetic field. We demonstrated that artifical cilia and flagella can be generated that pump fluid through microfluidic channels and that can swim through confined spaces. Current work aims at designing artificial cilia for use as active antifouling coatings and to transport particles.

PhD students: R. Zhang, S. Namdeo, S.N. Khaderi. In collaboration with J. den Toonder (Eindhoven University of Technology).

Publications (selection)

Last modified:26 July 2020 10.49 p.m.