Grand Séminaire d'Institut

Vendredi 12 Janvier 2018 à 11h00.

Harnessing soft interfaces with light and magnets: metafluidics, coffee ring diagnostics and dissipative 2D colloidal crystals

''We actuate various biological and synthetic systems (DNA, proteins, colloids, fluids, drops) by exploiting their intrinsic soft matter properties, either to perform useful processes in a novel and simpler way or to study curious/unexpected phenomena. In this talk, I will focus on some of these processes to illustrate the crucial role of interfaces in making such behaviors possible. I will first show that, using photosensitive surfactants, the optical modulation of interfacial energies [1] allows us to control the flow [2] and mixing [3] behaviors in microfluidic devices (light-driven microfluidics) [4] as well as to manipulate discrete drops (digital optofluidics) [5] and liquid marbles[6], with a simple LED as the sole power source. I will also describe a new principle of fluid actuation with magnets that can work on any kind of liquid (including nonmagnetic ones) without any magnetic particles [7] and I will explain how an interface can make a floating object move against the flow [6]! I will also illustrate the crucial role of interactions [8,9] with/at interfaces as well as interfacial/bulk flows [10] in evaporating colloidal suspension [11]. As a consequence, we can use light to cancel or modulate the so-called coffee-ring effect [8] as well as optically guide the deposition of any kind of particles into desired 2D or 3D patterns [10]. Following similar principles, I will further show how the simple visual inspection of a stain left after the evaporation of a drop containing proteins allows us to detect a pathogenic mutation, thus constituting a new concept for fast and low-cost diagnostics [12]. Finally, I will describe some recent works, in which we have prepared 2D colloidal crystals at the liquid-air interface in a new and extremely simple manner [13]. Notably, we have devised a way to realize dissipative crystals that can be dynamically switched between disordered and highly crystalline states [14].

[1] A. Diguet, R.-M. Guillermic, N. Magome, A. Saint-Jalmes, Y. Chen, K. Yoshikawa, D. Baigl, Angew. Chem. Int. Ed. 2009, 48, 9281
[2] A. Diguet, H. Li, N. Queyriaux, Y. Chen, D. Baigl, Lab Chip 2011, 11, 2666
[3] A. Venancio-Marques, F. Barbaud, D. Baigl, J. Am. Chem. Soc. 2013, 135, 3218
[4] D. Baigl, Lab Chip 2012, 12, 3637 (review)
[5] A. Venancio-Marques, D. Baigl, Langmuir 2014, 30, 4207
[6] N. Kavokine, M. Anyfantakis, M. Morel, S. Rudiuk, T. Bickel, D. Baigl, Angew. Chem. Int. Ed. 2016, 55, 11183
[7] J. Vialetto, M. Hayakawa, N. Kavokine, M. Takinoue, S. N. Varanakkottu, S. Rudiuk, M. Anyfantakis, M. Morel, D. Baigl, Angew. Chem. Int. Ed. 2017, 56, 16565
[8] M. Anyfantakis, D. Baigl, Angew. Chem. Int. Ed. 2014, 53, 14077
[9] M. Anyfantakis, Z. Geng, M. Morel, S. Rudiuk, D. Baigl, Langmuir 2015, 31, 4113
[10] S. N. Varanakkottu, M. Anyfantakis, M. Morel, S. Rudiuk, D. Baigl, Nano Lett. 2016, 16, 644
[11] M. Anyfantakis, D. Baigl. ChemPhysChem 2015, 16, 2726 (review)
[12] S. Devineau, M. Anyfantakis, L. Marichal, L. Kiger, M. Morel, S. Rudiuk, D. Baigl, J. Am. Chem. Soc 2016, 138, 11623
[13] Manuscript in preparation
[14] Manuscript in preparation
''