We are developing an arsenal of nanomaterials to adress societal issues while describing their formation.
We are a strong team of researchers specialized in nanosciences to build new materials with enhanced optical and mechanical properties.
Our knowledge span from the synthesis of the nanoproducts and their self-assembly to their structural characterization.
1 PhD position (ANR)
Spontaneous organization of mineral nanoparticles
The recent expansion of the field of “chimie douce” (soft chemistry) has led to a wide variety of anisotropic nanoparticles of all kinds of nature and shape (nanotubes, nanosheets, nanorods, etc.). These nanoparticles can often be dispersed in water or in organic solvents as colloidal suspensions. Quite often, these suspensions spontaneously organize in liquid-crystalline phases of different types (nematic, lamellar, columnar …).1,2 Moreover, these suspensions can also be destabilized to produce aggregates with well-defined structures.3-5 These two kinds of phenomena are very useful to manipulate and organize nanoparticles in order to obtain original physical properties. For example, by applying electric or magnetic fields, we can align anisotropic nanoparticles and even sometimes order them on a lattice.
At this moment, we have suspensions of various nanoparticles (clay and H3Sb3P2O14 nanosheets, imogolite nanotubes, CdSe and CeF3 nanoplatelets …) whose phase diagrams and original physical properties still need to be fully explored. This thesis will take place at the LPS which is a joint research unit of CNRS and University Paris-Saclay, specialized in condensed-matter physics. This PhD topic belongs to a more general project, funded by ANR, which aims at using the properties of these nanoparticles to elaborate sensors to monitor water quality.
 E.Paineau et al, Liquid Crystals Reviews, 1, 110 (2013).
 E.Paineau et al, Nature Communications, 7, 10271 (2016).
 B.Abécassis et al, Nanoletters, 14, 710 (2014).
 S.Jana et al, Angewandte Chemie, 55, 9371 (2016).
 S.Jana et al, Science Advances, 3, e1701483 (2017).
Techniques: X-ray scattering in-house and at large synchrotron radiation facilities (SOLEIL, ESRF), optical and electron microscopies, UV-vis spectroscopies, classical laboratories techniques of sample elaboration.
Required profile: Good level physicist or physical chemist. This thesis in experimental physics / physical chemistry will nevertheless involve a strong collaboration with chemists and theorists.
Funding: Project funded by ANR
Thesis advisors: Patrick Davidson, Jean-Christophe Gabriel
2 PhDs positions opening
The 2018 doctoral award campaign of the Ministry of Higher Education, Research and Innovation (MESRI in french) is open for ED 2MIB.
It takes place in 4 phases:
2/ Selection of only one candidate for each project before April 30th
3/ Audition of the candidates by the CIM Pole Jury of the ED (May 18th)
4/ Validation and publication of the results by the ED (June 15th).
click here for details and application:
The surprising self-organization of nanotubes in a very dilute columnar liquid-crystal phase
Liquid crystals have found wide applications in many fields ranging from detergents to information displays. They are an important class of “soft matter” and they are increasingly being used in the “bottom-up” self-assembly approach of the nano-structuration of materials. Moreover, liquid-crystalline organizations are frequently observed by biologists. A research team of the LPS, in collaboration with researchers from CEA-Saclay (NIMBE-LIONS), has recently discovered that one of the four major lyotropic liquid-crystal phases, the columnar one, is actually much more stable (by a factor 100 in concentration!) than considered up to now.
Nanotubes (or nanorods) in colloidal suspensions form a columnar liquid-crystal when they spontaneously organize parallel to each other, on a two-dimensional lattice perpendicular to their axes, like a bunch of pencils (Figure a). This organization was so far only expected in concentrated suspensions where the nanorods are close to contact. Here, researchers at LPS and LIONS have shown that very dilute suspensions of clay imogolite nanotubes form a columnar liquid-crystal. Imogolites are aluminosilicates (or aluminogermanates) that have raised increasing interest in the last decade. In contrast with carbon nanotubes, they are easily obtained by sol-gel processes at low temperature. Moreover, the presence of hydroxyl groups on their surface makes these nanotubes quite hydrophilic, which allows producing aqueous suspensions.
Figure: a) Schematic representation of the organisation of the nanotubes in the columnar hexagonal liquid-crystalline phase (a et b are the unit vectors of the hexagonal lattice) ; b) Small angle X-ray scattering pattern of the columnar phase aligned in an electric field; c) Structure factor showing the reflections (indicated by the red lines) of the hexagonal lattice.
Texture observations of very dilute suspensions (volume fraction ~ 0.3%) by polarized-light microscopy revealed the existence of an unexpected liquid-crystalline phase. Small-angle X-ray scattering measurements, performed at the SOLEIL synchrotron (Swing beamline) showed that this new phase is a columnar hexagonal liquid crystal (Figure b, c).
Despite the high dilution, the nanotubes are perfectly organized on a hexagonal lattice with a spacing (~ 80 nm) fifteen times larger than the nanotube diameter. This dilute liquid-crystal is so fluid that the nanotubes are easily aligned in an electric field, which is a prerequisite for future applications. This work has important implications for the statistical physics of colloidal suspensions of charged rod-like particles, like biopolymers, and their fundamental understanding. It also opens new perspectives, for instance, in the field of nanocomposite materials where the organization of anisotropic particles is required to improve physical properties.
Paineau E., Krapf, M.E.M., Amara M.S., Matskova, N.V., Dozov, I., Rouzière S., Thill, A., Launois, P. et Davidson, P.. A liquid-crystalline hexagonal columnar phase in highly-dilute suspensions of imogolite nanotubes. Nat. Commun., 7, 10271 (2016)
Erwan Paineau (email@example.com)
Patrick Davidson (firstname.lastname@example.org)
Laboratoire de Physique des Solides, CNRS, Univ. Paris Sud, Université Paris Saclay, 91405 Orsay cedex, France
Use of light to study nanoparticles self assembly
We use UV/Vis spectrometry and X-ray scattering tecniques (SAXS) to study nanoparticles super-structures. The structural study of the material is the first step before understanding its overall properties and considering applications. SAXS is an experimental technique used to study the structural properties of materials and gives information on the size and orientation of the nanoparticles, their arrangement, the characteristic interdistances and the possible long-range organization. In a scattering experiment, ordered phases give diffraction signals that are called Bragg peaks. Analysis of such signals requires adapting standard methods of crystallography to the nanoscale, as the relevant length scale is much larger than the atomic scale. UV/Vis spectrometry is used complementary to measure the collective optical properties. Both techniques can be used in situ to study self assembly's pathways.
A mesoporous material is a material containing pores with diameters between 2 and 50 nm. We are devising materials containing a mesoporous architecture to enhance size and shape selectivity for guest molecules or to template nanoparticles synthesis.
Construction of nanoscale devices is a crucial step toward the sucess of nanotechnologies in a variety of fields. Although construction by addition of individual building blocks might appear impossible without using nanomachines, it can actually be carried out by simply exploiting the different magnitude of attractive and repulsive interaction forces at the nanoscale. For example, gravity is negligible for nanoparticles, but other forces become dominant and require the nanoparticles to be coated with selected molecules. Thus, one can simply let the solvent evaporate and wait the nanoparticles to organize into ordered structures without any intervention. Such strategy is one of the core of the concept of self-assembly.
Gold and silver nanoparticles
Plasmonic nanoparticles (Au and Ag) have been object of fascination since ancient time for the preparation of stained glass. Such elementary building block are extremly robust and their use in monuments stand the test of time. A not too far example from the laboratory is the "Sainte-Chapelle du Palais" at "l'île de la cité" in Paris (see image, wikipédia). This phenomenon, commonly witnessed by everyone, originates from the electromagnetic properties of metallic nanoparticles.
Optical properties of nanoparticles
The strong optical properties of nanoparticles (e.g. plasmonic or semiconducting) can be tuned across the visible to the mid infra-red range by modifying their size and shape. When such nanoparticles are organized in ensembles, collective properties are obtained that differ from those of individual particles and the resulting optical properties can be further tuned and even amplified. In particular, plasmon coupling in small gaps (1–10 nm) between plasmonic nanoparticles results in intense electric fields (i.e.,hot-spots) that can be exploited for many purposes, such as sensing, biomaterials, metamaterials design, switching devices, and so forth.
|We are all working in the team MATRIX at the Laboratoire de Physique des Solides (LPS) in Orsay. The LPS is part of the vibrating Paris region fostering interaction with fellow researchers and visiting scientist.|
Cyrille Hamon obtained his Ph.D. from the University of Rennes 1 (France) under the supervision of Pascale Even-Hernandez and Valérie Marchi in 2013. He was a postdoctoral fellow in Luis Liz-Marzán laboratory (CIC Biomagune, Spain) from 2014 to 2016. He then joined the laboratories of Gaëlle Charron and Pascal Hersen in the University Paris Diderot.
He has just been appointed with a permanent CNRS position in the Laboratoire de Physique des Solides in Orsay.
His current interest focuses on devising new plasmonic architectures for sensing and catalytic applications.
After graduating with a chemical engineering degree from Ecole Supérieure de Physique et Chimie Industrielles de la ville de Paris, a PhD and an Habilitation à diriger des recherches, Patrick Davidson was appointed CNRS Research Director, in 2003, at Laboratoire de Physique des Solides of Université Paris-Sud in Orsay.
His research work focuses on the structural and physical properties of complex fluids such as molecular and polymer liquid crystals, colloidal suspensions and surfactant solutions. He has also recently been involved in the study of hybrid systems prepared by doping liquid-crystalline matrices with mineral nanoparticles. His favorite techniques are X-ray scattering, polarized-light microscopy, and magneto- and electro-optics. His research activity involves frequent contacts with chemists and theoretical physicists.
He is also presently in charge of the “Soft matter and biophysics” research axis of the LPS.
Marianne Impéror-Clerc has a permanent position at CNRS as ‘directrice de recherche’. She studied Physics at the ENS de Saint-Cloud (1986-1990) where she passed the ‘aggrégation de Physiques’ (1989) before obtaining her PhD (1992) and HdR ‘Habilitation à diriger des recherches’ (2007) at the Université Paris-Sud in Orsay.
Her research is devoted to structural studies of self-assembled systems and her favorite experimental tool is Small Angle Scattering using X-rays or neutrons (SAXS and SANS).
For example, for mesoporous materials, the control of the architecture of the porosity allows to optimize transport properties. Main goal is to control the nanostructure during the synthesis of such materials. For this, time-resolved scattering experiments allow to follow in real time the formation of the materials and to elucidate the mechanisms involved. Her research thus lies at the frontier between Soft Matter and Materials Chemistry.
She is alos regularly involved in activities about Crystallography for education and the general public (http://www.cristallo2014.u-psud.fr/)
Doru Constantin is co-director of the MATRIX research group.
He studied physics at the University of Bucharest and at the Ecole Normale Supérieure de Lyon and was awarded his PhD at the latter institution in 2002. After a Marie Curie Individual Fellowship at the University of Goettingen he obtained a permanent CNRS position at the LPS in 2005.
His activity revolves around the characterization of soft matter systems, often composed of an anisotropic medium doped with nanoparticles.
These studies are performed using modern, synchrotron-based techniques, such as time-resolved, dynamic, or surface-sensitive X-ray scattering and involve a substantial amount of modelling and analysis, using statistical theory or continuum media models.
7. Zhang, L.; Mikhailovskaya, A.; Constantin, D.; Foffi, G.; Tavacoli, J.; Schmitt, J.; Muller, F.; Rochas, C.; Wang, N.; Langevin, D.; Salonen, A. Journal of Colloid and Interface Science 2016, 463, 137-144.
12. Kredentser, S.; Bugaeva, L.; Derzhypolski, A.; Cherepanov, D.; Malynych, S.; Castro, N.; Davidson, P.; Reznikov, Y. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2016, 506, 774-781.
15. Hamon, C.; Henriksen-Lacey, M.; La Porta, A.; Rosique, M.; Langer, J.; Scarabelli, L.; Montes, A. B. S.; González-Rubio, G.; de Pancorbo, M. M.; Liz-Marzán, L. M.; Basabe-Desmonts, L. Advanced Functional Materials 2016, 26, (44), 8053-8061.
19. Bodelon, G.; Montes-Garcia, V.; Lopez-Puente, V.; Hill, E. H.; Hamon, C.; Sanz-Ortiz, M. N.; Rodal-Cedeira, S.; Costas, C.; Celiksoy, S.; Perez-Juste, I.; Scarabelli, L.; La Porta, A.; Perez-Juste, J.; Pastoriza-Santos, I.; Liz-Marzan, L. M. Nat Mater 2016, 15, (11), 1203-1211.
20. Riou, O.; Lonetti, B.; Tan, R. P.; Harmel, J.; Soulantica, K.; Davidson, P.; Mingotaud, A.-F.; Respaud, M.; Chaudret, B.; Mauzac, M. Angewandte Chemie International Edition 2015, 54, (37), 10811-10815.
40. Riou, O.; Lonetti, B.; Davidson, P.; Tan, R. P.; Cormary, B.; Mingotaud, A.-F.; Di Cola, E.; Respaud, M.; Chaudret, B.; Soulantica, K.; Mauzac, M. The Journal of Physical Chemistry B 2014, 118, (11), 3218-3225.
52. Bizien, T.; Even-Hernandez, P.; Postic, M.; Mazari, E.; Chevance, S.; Bondon, A.; Hamon, C.; Troadec, D.; Largeau, L.; Dupuis, C.; Gosse, C.; Artzner, F.; Marchi, V. Small 2014, 10, (18), 3707-3716.
55. Tresset, G.; Le Coeur, C.; Bryche, J.-F.; Tatou, M.; Zeghal, M.; Charpilienne, A.; Poncet, D.; Constantin, D.; Bressanelli, S. Journal of the American Chemical Society 2013, 135, (41), 15373-15381.
57. Paineau, E.-N.; Philippe, A. M.; Antonova, K.; Bihannic, I.; Davidson, P.; Dozov, I.; Gabriel, J. C. P.; Impéror, M.; Levitz, P.; Meneau, F.; Michot, L. J. Liquid Crystals Reviews 2013, 1, (2), 110-126.
85. Paineau, E.; Dozov, I.; Antonova, K.; Davidson, P.; Impéror, M.; Meneau, F.; Bihannic, I.; Baravian, C.; Philippe, A. M.; Levitz, P.; Michot, L. J. IOP Conf. Series: Materials Science and Engineering 2011, 18, 0622005.
87. Manet, S.; Schmitt, V.; Impéror, M.; Zholobenko, V. L.; Durand, D.; Oliveira, C. L. P.; Pedersen, J. S.; Gervais, C.; Baccile, N.; Babonneau, D.; Grillo, I.; Rochas, C. J. Phys. Chem. B 2011, 115, 11330-11344.
101. De Silva, J. M.; Petermann, D.; Kasmi, B.; Impéror, M.; Davidson, P.; Pansu, B.; Meneau, F.; Perez, S.; Paineau, E.; Bihannic, I.; Michot, L. J.; Baravian, C. J. Phys. Conf. Ser. 2010, 247, 012052.
102. Davidson, P. In Giant electric field induced orientational order in isotropic aqueous colloidal suspensions driven by electric double layer polarization, Playing Colloidal Mikado II, 2010, 2010; 2010.