Abstract

Active matter systems are composed of constituents that consume energy in order to move or exert mechanical forces, constantly driving themselves away from equilibrium [1]. Examples of active particles at the mesoscopic scale are living, such as bacteria, or artificial, such as active colloids [2,3] Experiments on spherical man-made self-propelled colloids have shown that active particles present interesting emergent collective properties [4–6], such as motility-induced phase separation (MIPS), involving spontaneous assembly of particles due to the persistence of their direction of motion [7]. An example of colloids undergoing MIPS under suitable conditions are Active Brownian Particles (ABP), i.e. self-propelled Brownian particles interacting with each other via a purely repulsive potential [8]. In order to design novel functional materials, one might need to gain control on the self-assembly process of active colloids. With this goal in mind, we have explored the competition between activity and a broad range of interactions in a suspension of active colloids, considering either isotropic (strongly repulsive [9], attractive [10,11], micelle-inducing potential [12]) or anisotropic (Janus-like) potential¹³, unravelling the relevance of hydrodynamics [11,14] and investigating mixtures of active/passive particles [15,16,17]. REFERENCES : [1] C. Bechinger et al. Rev. Mod. Phys. 88, 045006 (2016). [2] W.F. Paxton et al. Chem. Commun. 441, 3 (2005). [3] S. Fournier-Bidoz et al. J. Am. Chem. Soc. 126, 13424 (2004). [4] S. Thutupalli, R. Seemann, S. Herminghaus New J. Phys. 13, 073021 (2011). [5] D. Nishiguchi, Masaki S. Phys. Rev. E 92 , 052309 (2015). [6] I. Buttinoni, J. Bialké, F. Kümmel, H. Löwen, C. Bechinger, T. Speck. Phys.Rev. Lett. 110, 238301 (2013). [7] M.E. Cates, J. Tailleur. Annu. Rev. of Condens. Matt. Phys. 6, pp. 219-244 (2015). [8] S.Mallory, C.Valeriani and A.Cacciuto Annual review of Physical Chemistry, 69 59 (2018) [9] Diego Rogel Rodriguez, Francisco Alarcon, Raul Martinez, Jorge Ramirez, and Chantal Valeriani, in preparation (2018) [10] B. Mognetti, A. Saric, S. Angioletti-Uberti, A. Cacciuto, C. Valeriani and D. Frenkel Phys.Rev.Lett., 111 245702 (2013) [11] F.Alarcon, C.Valeriani and I.Pagonabarraga Soft Matter 10.1039/C6SM01752E (2017) [12] C.Tung, J.Harder, C.Valeriani and A.Cacciuto, Soft Matter 12 555 (2016) [13] S.Mallory, F.Alarcon, A.Cacciuto and C.Valeriani New Journal of Physics (2017) [14] F.Alarcon, E.Navarro, C.Valeriani and I.Pagonabarraga, PRE submitted (2018) [15] J.Harder, S.Mallory, C.Tung, C.Valeriani and A.Cacciuto, J.Chem.Phys. 141 194901 (2014) [16] R.Martinez, F.Alarcon, D.R.Rodiguez, J.L.Aragones and C.Valeriani, EPJE 41 91 (2018) [17] Diego Rogel Rodriguez, Francisco Alarcon, Raul Martinez, Jorge Ramirez, and Chantal Valeriani, under review JCP (2018) CO-AUTHORS: Francisco Alarcon, Raul Martinez, Juan Luis Aragones, Jorge Ramirez, Stewart Mallory, Ignacio Pagobanarraga, Angelo Cacciuto