ANR project: For WATER Quality Monitoring – 4WATER
The water crisis is the #1 global risk based on impact to society as announced by the World Economic Forum in January 2015 . Indeed, groundwater is a scarce resource as it only account for 0.3% of the Earth's total freshwater reserves. And already, 663 million people - 1 in 10 - lack access to safe water and 2.4 billion people - 1 in 3 - lack access to adequate sanitation (including 1/3 of all schools)[2,3] which has been shown to strongly impact local water quality and population’s health  Even when safe water is accessible, there can be great variability in its composition depending on many environmental and human factors , which can sporadically render it unsafe. Despite this, little is known of this variabilities and interplays because no global and permanent monitoring of these freshwater resources. Hence the objective of this proposalto develop a new low cost, multi-analyte water quality monitoring solution.
The project is coordinated by Jean-Christophe P. Gabriel, Nanoscience Research Director at CEA/NIMBE (Nanosciences et innovation pour les matériaux, la biomédecine et l'énergie), with the following partners:
The help received of the ANR was of 655 966 euros
Beginning and duration of the scientific project: December 2017 - 42 Months
Ph. D. Student that worked on this project:
1) "Method for protecting air-sensitive or evaporation-sensitive objects." Jean Christophe Gabriel, Monika Spano, Fatima-Ezzahra Hami, WO/2021/089957
=> Available for Licensing
A colloidal suspension of H3Sb3P2O14 nanosheets in water (left) displays three different phases with clear interfaces. Associated SAXS images (middle) obtained at ESRF synchrotron proves that these phases have different structural organisations (sketched on the right).
1) Isotropic, nematic, and lamellar phases in colloidal suspensions of nanosheets
Davidson, P; Penisson, C; (...); Gabriel, JCP
June 26th, 2018, Proceeding of the National Academy of Sciences of the USA, 115(26) 6662-6667
Abstract: The phase diagram of colloidal suspensions of electrically charged nanosheets, such as clays, despite their many industrial uses, is not yet understood either experimentally or theoretically. When the nanosheet diameter is very large (similar to 100 nm to 1 µm), it is quite challenging to distinguish the lamellar liquid-crystalline phase from a nematic phase with strong stacking local order, often called "columnar" nematic. We show here that newly upgraded smallangle X-ray scattering beamlines at synchrotron radiation facilities provide high-resolution measurements which allow us to identify both phases unambiguously, provided that single domains can be obtained. We investigated dilute aqueous suspensions of synthetic Sb3P2O143- nanosheets that self-organize into two distinct liquid-crystalline phases, sometimes coexisting in the same sample. Close examination of their X-ray reflection profiles in the directions perpendicular to the director demonstrates that these two mesophases are a columnar nematic and a lamellar phase. In the latter, the domain size reaches up to similar to 20 µm, which means that each layer is made of > 600 nanosheets. Because the lamellar phase was only rarely predicted in suspensions of charged disks, our results show that these systems should be revisited by theory or simulations. The unexpected stability of the lamellar phase also suggests that the rims and faces of Sb3P2O143- nanosheets may have different properties, giving them a patchy particle character.
2) Methods for dispersing carbon nanotubes for nanotechnology applications: liquid nanocrystals, suspensions, polyelectrolytes, colloids and organization control.
Sergio Manzetti, Jean-Christophe P. Gabriel, International Nano Letters 9 (1), 31-49 (2019).
Abstract: Carbon nanotubes (CNTs) are a central part of advanced nanomaterials and are used in state-of-the-art technologies, based on their high tensile strength, excellent thermal transfer properties, low-band gaps and optimal chemical and physical stability. Carbon nanotubes are also intriguing given their unique -electron-rich structures, which opens a variety of possibilities for modifications and alterations of their chemical and electronic properties. In this review, a comprehensive survey of the methods of solubilization of carbon nanotubes is presented, forming the methodological foundation for synthesis and manufacturing of modified nanomaterials. The methods presented herein show that solubilized carbon nanotubes have a great potential in being applied as reactants and components for advanced solar cell technologies, nanochemical compounds in electronics and as parts in thermal transfer management. An example lies in the preservation of the aromatic chemistry in CNTs and ligation of functional groups to their surfaces, which confers CNTs with an optimal potential as tunable Schottky contacts, or as parts in nanotransistors and nano-resistances. Future nanoelectronic circuits and structures can therefore depend more and more on how carbon nanotubes are modified and functionalized, and for this, solubilization is oftena critical part of their fabrication process. This review is important, is in conjecture with the latest developments in synthesis and modification of CNTs, and provides the know-how for developing new CNT-based state-of-the-art technologies, particularly with emphasis on computing, catalysis, environmental remediation as well as microelectronics.
3) Destabilization of the Nematic Phase of Clay Nanosheet Suspensions by Polymer Adsorption
Karin El Rifaii, Henricus H. Wensink, Thomas Bizien, Jean-Christophe P. Gabriel, Laurent Michot, Patrick Davidson, Langmuir 36(42) 12563–12571 (2020)
Abstract: Complex aqueous mixtures comprised of swelling clays and hydrosoluble polymers naturally occur in soils and play a major role in pedogenesis. They are also very often used for formulating oil-well drilling fluids, paints, and personal-care products. The suspensions of some natural clays, thanks to their large nanoparticle aspect ratio, spontaneously form nematic liquidcrystalline phases where the particles align parallel to each other, which affects their flow properties. We observed that adding small amounts of hydrosoluble polymers to these clay suspensions destabilizes the nematic phase with respect to the isotropic (disordered) phase. The polymers that we used (poly(ethylene oxide) and dextran) were too small to adopt particle-bridging conformations and small-angle X-ray scattering experiments showed that the structure of the nematic phase is not altered by polymer doping. However, the adsorption isotherm shows that the macromolecules adsorb onto the clay nanosheets, effectively coating them with a polymer layer. Our extension of Onsager's theory for polymer-coated platelets properly captures the experimental phase diagram and shows how the nematic phase destabilization can be due to the polymer adsorbing more on the platelet faces than at the rim. Because the flow properties of the nematic phase are very different from those of the isotropic phase, the presence or absence of the former phase is an important factor to be determined and considered to explain the rheological behavior of these complex systems.
4) Fine tuning of the structural colors of photonic nanosheet suspensions by polymer doping
Karin El Rifaii, Henricus H. Wensink, Claire Goldmann, Laurent Michot, Jean-Christophe P. Gabriel, Patrick Davidson, Soft Matter 17(41) 9280-9292 (2021)
Abstract: Aqueous suspensions of nanosheets are readily obtained by exfoliating low-dimensional mineral compounds like H3Sb3P2O14. The nanosheets self-organize, at low concentration, into a periodic stack of membranes, i.e. a lamellar liquid-crystalline phase. Due to the dilution, this stack has a large period of a few hundred nanometres, it behaves as a 1-dimensional photonic material and displays structural colours. We experimentally investigated the dependence of the period on the nanosheet concentration. We theoretically showed that it cannot be explained by the usual DLVO interaction between uniform lamellae but that the particulate nature of nanosheet-laden membranes must be considered. Moreover, we observed that adding small amounts of 100 kDa poly(ethylene oxide) (PEO) decreases the period and allows tuning the colour throughout the visible range. PEO adsorbs on the nanosheets, inducing a strong reduction of the nanosheet charge. This is probably due to the Lewis-base character of the EO units of PEO that become protonated at the low pH of the system, an interpretation supported by theoretical modeling. Oddly enough, adding small amounts of 1 MDa PEO has the opposite effect of increasing the period, suggesting the presence of an additional intermembrane repulsion not yet identified. From an applied perspective, our work shows how the colours of these 1-dimensional photonic materials can easily be tuned not only by varying the nanosheet concentration (which might entail a phase transition) but also by adding PEO. From a theoretical perspective, our approach represents a necessary step towards establishing the phase diagram of aqueous suspensions of charged nanosheets.
Abstract: Imparting liquid-crystal (LC) materials with the plasmonic properties of metal nanoparticles is actively pursued for applications. We achieved this goal by synthetizing gold nanoparticles onto clay nanosheets, leading to nematic nanocomposite suspensions. Optical observations and structural analysis show the growth of the gold nanoparticles without altering the LC properties of the nanosheets. These colloids display plasmonic structural colours and they can be aligned by an electric field, which is relevant for fundamental and materials chemistry of colloidal LC.