Active particles with anisotropic shape and flexibility
Biological microorganisms rely on changes in their shape to create and direct their motion. In contrast, experimental realizations of synthetic self-propelled systems are currently mostly spherical and rigid. These experimental limitations preclude a fundamental understanding of how anisotropic shape and conformational flexibility affect a microswimmers individual and collective behavior.
In this talk, I will demonstrate that 3D microprinting can be exploited to create anisotropic synthetic microswimmers of virtually any shape, from spheres with spikes to microscopic boats.[1] Using this technique to print a class of anisotropic particles ranging from spheres to bent and straight rods, I will demonstrate that an anisotropic swimmer shape dramatically enhances cluster formation. We find that the clustering dynamics is governed by a single scaling parameter that depends on particle density and shape only, due to an interplay between interlocking probability and cluster stability.[2] Finally, I will show a range of intriguing behavior that is obtained when combining activity with flexibility.
Our work provides key insights into how shape can be used to rationally design out-of-equilibrium self-organization, which is key to creating active functional materials.
[1] R.P. Doherty, T. Varkevisser, M. Teunisse, J. Hoecht, S. Ketzetzi, S. Ouhajji, D.J. Kraft, Catalytically propelled 3D printed microswimmers, Soft Matter, DOI: 10.1039/d0sm01320j (2020); Highlighted in Nature News in Brief, 587, p. 527 (2020) and chosen as one of the “Images of the Year 2020” in Nature (Dec 2020); covered by media and news globally
[2] S. Riedel, L. Hoffmann, L. Giomi, D.J. Kraft, Designing highly efficient lock-and-key interactions in anisotropic active particles, arXiv:2308.09992 [cond-mat.soft] (2023)