Poster abstracts P01 Penetration of a model membrane by a self-propelled active A. Daddi-Moussa-Ider particle P02 The squirmer model and beyond F. Fadda P03 Theoretical Investigation of Structure Formation by Magne- V. Telezki totactic Bacteria P04 Active Nematics Formed by Bacteria in Patterned R. Koizumi Chromonics P05 Self-propulsion of Camphor Symmetric Interfacial Swim- D. Boniface mers P06 Microswimmers self-propelled by Thermophoresis S. Roca-Bonet P07 Active Brownian filaments in dilute solution A. Mart´ın-Gomez´ P08 Scattering of E. coli at surfaces M. Mousavi P09 Light dependent motility of microalgae induces pattern for- A. Fragkopoulos mation in confinement P10 Longwave nonlinear theory for chemically active droplet di- M. Abu Hamed vision instability P11 Bead-spring modelling microswimmers S. Ziegler P12 Light-driven Janus microswimmers in dense colloidal ma- T. Huang trix P13 Active Brownian Particles in Crowded Media A. Liluashvili P14 Evolution in range expansions with competition at rough S. Chu boundaries P15 Mode-Coupling Theory for Active Brownian Particles J.Reichert P16 Structure and dynamics of a self-propelled semiflexible fil- S. P. Singh ament P17 IHRS Biosoft T. Auth P18 IHRS Biosoft T.Auth P19 Pairing, waltzing and scattering of chemotactic active col- S. Saha loids P20 Instability in settling array of discs R. Chajwa P21 Self-propelled particles in anisotropic environments A. R. Sprenger P22 A phase field crystal approach to active systems with inertia D. Arold P23 Ring polymers are much stronger depleting agents than lin- I. Chubak ear ones P24 Enhanced rotational diffusion of squirmers in viscoelastic K. Qi fluids P25 Dynamics of confined phoretic colloids K. R. Prathyusha P26 Enhanced dynamic heterogeneity in model active glass K. Paul forming liquids P27 Tracer Diffusion in a Dense Active Bath L. Abbaspour P28 pH dependence of Swimming Direction of Janus Micromo- F. Ruhle¨ tors P29 Role of pH in Micro-swimming N. Moller¨ P30 Chemical micromotors that self-assemble T. Yu P31 Active apolar doping determines routes to colloidal clusters H. Massana-Cid and gels P32 Efficient photocatalytic bismuth vanadate microparticles for S. Heckel active propulsion P33 Polarization of Brownian swimmers with spatiotemporally S. Auschra heterogeneous activity P34 Active Brownian heat engine S. Steffenoni P35 Dependence of Swimming Direction of Janus Micromotors N. Murty on pH P36 Photo-Induced Motion of Polymer Brush Coated Small Par- M. Sokolowski ticles P37 Linear rheology of reversibly cross-linked biopolymer net- H. E. Amuasi works P38 Brownian molecules formed by delayed harmonic interac- D. Geiß tions P39 Collective rotations of active particles interacting with ob- Z. Mokhtari stacles P40 Influence of catalysts on the propulsion path of micromotors P. Chattopadhyay P41 Active matter systems can exhibit coexisting patterns of T. Kruger¨ competing symmetries P42 Impact of Brush/Water Interface on the self-propulsion of M. Heidari Janus Particles P43 Tissue Mechanics: Stokes Flow in Confluent Cell Simula- C. P. Beatrici tions P44 Self-propelled rods with quorum sensing T. Auth P45 Shape and motility of composite active agents with internal C. Abaurrea Velasco degrees of freedom P46 A Model For The Possible Role Of Substrate Rigidity For A.N. Simsek Bacterial Migration And Colony Formation P47 Collective intercellular communication through ultra-fast A. J. T. M. Mathijssen hydrodynamic trigger waves P48 Collective motion in biological systems: Langevin Equa- L. Amallah tion investigation P49 The tortoise and the hare: how collective behaviours within O. J. Meacock bacterial biofilms select for cells that move more slowly P50 Filamentous Active Matter: Band Formation, Bending, G. A. Vliegenthart Buckling, and Defects P51 Sperm motility in modulated microchannels S. Rode P52 Spontaneous Spatiotemporal Ordering of Shape Oscilla- M. Campo tions Enhances Cell Migration P53 Actuation of particles in modulated Poiseuille flow W. Schmidt P54 Multiparticle Collision Dynamics Modeling of Nematic S. Mandal Liquid Crystal with Variable Order Parameter P55 A minimal model for fluid-like collective cell migration D. Sarkar P56 Hydrodynamic interactions of beating cilia A. Solovev P01 Penetration of a model membrane by a self-propelled active particle A. Daddi-Moussa-Ider1, S. Goh1, B. Liebchen1, C. Hoell1, A. J. T. M. Mathijssen2, F. Guzmán-Lastra1,3, C. Scholz1, A. M. Menzel1, and H. Löwen1. 1Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany 2Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA 3Facultad de Ciencias, Universidad Mayor, Av. Manuel Montt 367, Providencia, Santiago de Chile, Chile E-mail: [email protected] We present a model to describe the interaction of a self-propelling active particle with a minimal membrane system, allowing for both penetration and trapping events. We numerically calculate the state diagram of this system, the membrane shape, and its dynamics, finding that the active particle may either get trapped near the membrane or penetrates through it. We show that the membrane can either be permanently damaged or recover its initial shape by self-healing. We then systematically derive a continuum theory allowing to accurately predict most of our results analytically. Our results might be useful to predict mechanical properties of synthetic membranes. References [1] A. Daddi-Moussa-Ider, S. Goh, B. Liebchen, C. Hoell, A. J. T. M. Mathijssen, F. Guzmán- Lastra, C. Scholz, A. M. Menzel, and H. Löwen. Membrane penetration and trapping of an active particle, J. Chem. Phys. 150, 064906 (2019) P02 The squirmer model and beyond F.Fadda1, J.J.Molina1 and R.Yamamoto1,2 1Department of Chemical Engineering, Kyoto University, Kyoto, 615-8510, Japan 2Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan E-mail: [email protected] The squirmer model introduced by Lighthill and later extended by Blake [1] allows the description of microorganisms such as algae and bacteria. It consists in a spherical particle with a prescribed tangential velocity field, neglecting the radial component, responsible for the self-propulsion. If the microorganism repels fluid along its axis and attracts it to the sides it is called pusher (like the bacterium Escherichia Coli); in the opposite case it is called puller (like the alga Chlamydomonas Reinardtii) [2]. In this study the squirmer model is incorporated into the Smoothed Profile Method, an efficient calculation scheme to simulate solid objects into a fluid taking fully into account the hydrodynamics [3], which has already been successfully used in the past to study collective motion and interactions of squirmers [4]. Now the traditional squirmer model, which considers only a purely tangential surface velocity neglecting the radial one, is updated introducing also an azimuthal component of velocity to give a more realistic description of the motion of microorganisms like bacteria whose flagellar filaments attached to the cell bodies rotate in a counterclockwise direction. This is also accompanied by a counter rotation of the cell body and the translation of the bacterium in a general motion resembling a corkscrew [2,5]. We start analyzing the dynamics of a single squirmer with the intention in the future to investigate deeper the mutual interactions of a couple of them and the collective dynamics. References [1] M.J.Lighthill, Commun. Pure Appl. Math. 5, 109 (1952); J.R.Blake, J. Fluid Mech. 46, 199 (1971). [2] E.Lauga and T.Powers, Rep. Prog. Phys. 72, 096601 (2009); J.Elgeti, R.G.Winkler and G.Gompper, Rep. Prog. Phys. 78, 056601 (2015); E.Lauga, Annu. Rev. Fluid Mech. 48, 105-130 (2016). [3] Y.Nakayama and R.Yamamoto, Phys. Rev. E 71, 036707 (2005); Y.Nakayama, K.Kim and R.Yamamoto, Eur. Phys. J. E 26, 361 (2008). [4] J.J.Molina, Y.Nakayama and R.Yamamoto, Soft Matter 9, 4923 (2013); N.Oyama, J.J.Molina and R.Yamamoto, Phys. Rev. E 93, 043114 (2016); N.Oyama, J.J.Molina and R.Yamamoto, Eur. Phys. J. E 40, 95 (2017). [5] O.S.Pak and E.Lauga, J. Eng. Math. 88, 1-28 (2014). P03 Theoretical Investigation of Structure Formation by Magnetotactic Bacteria Vitali Telezki, Omar Muñoz and Stefan Klumpp Institute for Nonlinear Dynamics, University of Göttingen, Germany E-mail: [email protected] [email protected] [email protected] Magnetotactic bacteria are bacteria that orient in magnetic fields with the help of a specific cell organelle, the magnetosome chain, a chain of membrane-enclosed magnetic iron-oxide nanocrystals. The resulting orientation allows the bacteria to navigate along magnetic field lines. Because of the interplay between different physical interactions such as steric, hydrody- namic and magnetic interactions, complex collective behaviour is expected to emerge in dense systems of these bacteria. We use Brownian dynamics simulations to investigate the collective behaviour of magnetotactic bacteria. In a first step, we focus on the structure formation of active Brownian particles with a magnetic dipole moment. We analyse what structures can emerge and how they depend on the self-propulsion velocity, the magnetic moment and other attributes of the swimmers. References [1] S. Klumpp, C.T. Lefevre, M. Bennet, D. Faivre, Phys Rep. in press/available online, DOI: 10.1016/j.physrep.2018.10.007 P04 Active Nematics Formed by Bacteria in Patterned Chromonics