Microscopic Engine Powered by Critical Demixing Falko Schmidt, Alessandro Magazzu, Agnese Callegari, Luca Biancofiore, Frank Cichos & Giovanni Volpe
APS March Meeting 2018, Los Angeles (CA), USA
5-9 March 2018
During the last few decades much effort has gone into the miniaturization of machines down to the microscopic scale with robotic solutions indispensable in modern industrial processes and play a central role in many biological systems. There has been a quest in understanding the mechanism behind molecular motors and several approaches have been proposed to realize artificial engines capable of converting energy into mechanical work. These current micronsized engines depend on the transfer of angular momentum of light, are driven by external magnetic fields, due to chemical reactions or by the energy flow between two thermal reservoirs [1-5]. Here we propose a new type of engine that is powered by the local, reversible demixing of a critical binary liquid. In particular, we show that an absorbing, optically trapped particle performs revolutions around the optical beam because of the emergence of diffusiophoresis and thereby produces work. This engines is adjustable by the optical power supplied, the temperature of the environment and the criticality of the system.
1. P.A. Quinto-Su, Nat. Comm. 5 (2014).
2. V. Blickle et al., Nat. Phys. 8 (2012).
3. I.A. Martinez et al., Nat. Phys. 12 (2016).
4. S.L. Neale et al., Nat. Mater. 4 (2005).
5. A. Argun et al., arXiv preprint (2017)
Session R57: Active Matter I
8:00 AM–11:00 AM, Thursday, March 8, 2018
LACC Room: 518
Sponsoring Units: GSOFT DBIO GSNP
Chair: Paulo Arratia, Univ of Pennsylvania
Active Matter Alters the Growth Dynamics of Coffee Rings
Tuğba Andaç, Pascal Weigmann, Sabareesh K. P. Velu, Erçağ Pinçe, Agnese Callegari, Giorgio Volpe & Giovanni Volpe
We experimentally demonstrate the light-controlled assembly of active colloidal molecules from a suspension of two species of passive microspheres.When light is shone on the sample, the active molecules form and acquire motility through non-reciprocal interactions between their passive components. As their size grows, they feature a complex array of behaviors, becoming propellers, spinners and rotators. Their shape and functionality can be tuned by applying periodic illumination. We also provide a theoretical model allowing to predict the complete table of emerging active molecules and their properties in quantitative agreement with the experiments.
Biophotonics feature: introduction
Paolo Campagnola, Daniel Cote, Francesco Pavone, Peter Reece, Vivek J. Srinivasan, Tomasz Tkaczyk & Giovanni Volpe
Biomedical Optics Express 9(3), 1229–1231 (2018)
Rafal Piwowarczyk defended his Master thesis in Complex Adaptive Systems at Chalmers University of Technology on 19 February 2018
Title: Influence of Delay on the Vicsek Model
The aim of this work is to show that sensorial delay influences the behaviour of self-propelling agents using self-aligning interactions. The model was based on the Vicsek model, which is a two-dimensional system of self-propelling particles that are able to detect and align with each other within a certain radius. We prove that the introduction of short delays favours cluster and swarm formation, while extending the delay to higher values or implementation of negative delays significantly harms this process. We introduce a global clustering parameter, which is based on the use of the Voronoi tessellation, which allows us to measure the emergence of clusters. The sensorial delay might play a crucial role in systems that exhibit swarming behaviours and it’s better understanding can result in the construction of key tools for the realisation and manipulation of complex networks of autonomous robots.
Name of the master programme: MPCAS – Complex Adaptive Systems Supervisor: Giovanni Volpe, Department of Physics, University of Gothenburg Examiner: Giovanni Volpe, Department of Physics, University of Gothenburg Opponent: Freddie Ogemark, MP Complex Adaptive Systems, Department of Physics, Chalmers University of Technology
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