Reseach themes

My principal research interests are on polymers and colloidal science and revolve around the development of new synthetic methods and concepts to control the structure and functional properties of colloidal materials. My research activities include both the synthesis of dispersed colloidal systems and the design of materials formed from them, and is organized around three major research axes.

A) Synthesis of hybrid particles and complex nano-objects with controlled morphologies

B) Living and/or controlled polymerizations

C) Particles and functional materials in response to environmental and societal challenges

Current projects

 

Pickering stabilization of latex particles

Among the main thrusts of my current activities on the first axis is the synthesis of surfactant-free latexes stabilized by inorganic particles by conventional emulsion or dispersion polymerization. We have pioneered the use of nanosized clay platelets as solid stabilizers of a range of vinyl polymers leading to clay-armored latexes that can be processed into honeycomb structured nanocomposite film materials with remarkable mechanical properties. We currently develop innovative synthetic strategies toward the formation of a variety of inorganic-armored latex particles with desirable functionalities (anti-UV, magnetic, antibacterial, etc.). In collaboration with Nida Sheibat-Othman of the LAGEPP, we have also recently worked on the modeling of the polymerization process using Laponite clay as stabilizer (see now).

Vitrimer latexes and vitrimer-thermoplastic alloys

(collaboration with D. Montarnal and E. Drockenmuller (IMP, Lyon))

Vitrimers represent a new class of crosslinked polymers, where the crosslinks are in permanent exchange through chemical reactions in dynamic equilibrium. Such networks are thus insoluble like thermosets, but flow when heated like thermoplastics. While more and more well-known equilibrium reactions (transesterifications, cross-metathesis, etc.) are currently finding a revival in vitrimers, this versatile concept was so far limited to bulk materials. At CP2M, we recently reported the first example of epoxy-acid vitrimer latexes by miniemulsion polymerization and demonstrated the formation of crosslinked polymer films by sintering of the particles at high temperature (see now). Building on this success, we now want to develop interpenetrating or semi-interpenetrated vitrimer/thermoplastic polymer networks, combining fast exchange dynamics and nanostructured morphologies

Free radical emulsion photopolymerization under near infrared (NIR) light

(collaboration with E. Lacôte of the LHCEP, Lyon)

Photopolymerizations have witnessed a huge interest over the past few years for the production of a variety of polymeric materials. While most traditional photoinitiating systems employ UV radiation to generate the active species, the use of longer wavelengths such as visible or near infrared (NIR) light is attracting increasing attention. Indeed, the shift to longer wavelength allows a better penetration of light and enable to overcome the limitations induced by the light scattering making these photoinitiating systems compatible with turbid media, and especially with conventional emulsion polymerization. Following our previous works in visible-light emulsion photopolymerization using N-Heterocyclic carbene-boranes as co-initiators (ANR PHOTO-B), we now wish to use NIR light with single or multiphoton excitations to trigger the photopolymerization of styrenic or (meth)acrylic monomers in dispersed media using redox initiators or NIR dyes specifically designed for multiphoton absorption and compatible with water or hydroalcoolic media (ANR IR-EMULSION).

RDRP-mediated synthesis of organic/inorganic nanostructured colloidal materials

The research activities carried out under this heading will build on the strong expertise gained over the past ten years on the use of living polymers (macroalkoxyamines or macroRAFTs) to promote the nucleation and growth of hydrophobic polymers on the surface of inorganic particles, leading to the formation of composite latexes of various morphologies. We now wish to deepen our understanding of the underlying mechanisms with the view to further improve morphological control and create robust and predictable organic/inorganic assemblies. In parallel, we will extend the approach to a larger range of inorganic materials of potential industrial interest such as zinc oxide and progress towards industrially viable materials and processes, with emphasis on microstructure-properties relationships.

Composite latexes for thermochromic coating applications

(collaboration with J. Faucheu and R. Charrière of EMSE, St Etienne)

This multidisciplinary project aims at developing a nanocomposite thermoactive polymer coating containing vanadium dioxide (VO₂) particles. VO₂ is a thermochromic compound known to undergo an Insulator-Metal Transition leading to a high dielectric constant change, in particular in the near infrared. Above the transition temperature (Tc), VO₂ behaves like a metal and reflects the sun light while below Tc, near IR wavelengths are transmitted by the material. The coatings developed within this project will thus exhibit a different behavior in cold (winter) conditions and hot (summer) conditions to perform an optimized thermal effect on the coated substrate (ANR THERMOCOAT).

Supervision and partners

I am currently (co)supervising :

•  Ms. Nedjma Beldjoudi (PhD Student, 2022-2025), who is working on the synthesis of non aqueous pigmented polymeric dispersions for use as electrophoretic inks, in the frame of the ANR project DEFINED. Nedjma is cosupervised with my colleagues Dr. Cyril Brochon (LCPO, Bordeaux), Pr. Stéphane Daniele and Dr. Fabrice Brunel.
• Mr. Enrique Folgado a post-doctoral fellow who is funded by the ANR THERMOCOAT coordinated by Dr. Renée Charrière (EMSE, St Etienne). Enrique is working on the development of a thermooactive coating loaded with thermochromic vanadium dioxide nanoparticles for building energy saving applications.
• Mr. Leo Gazetta (PhD Student 2021), who is working on the scalable synthesis of nanostructured thermoplastic-based vitrimer latexes and film materials through the combination of conventional radical polymerization and different cross-link exchange chemistries (transesterification, trans-N-alkylation, etc.) in multiphase systems. Leo is funded by the ANR project MATVIT and is cosupervised with my colleagues Dr. Damien Montarnal and Pr. Eric Drockenmuller (IMP, Lyon). Leo benefits from the highly stimulating scientific environment of the VITRIMAT ITN project coordinated by the University Claude Bernard Lyon1.
• Ms. Huanhuan Ma (PhD Student 2021-2025), who is working on the self-assembly of novel electrosterically stabilized inorganic colloids to form composite particles and film materials with tailored microstructures and properties. Huanhuan has been awarded a Chinese Government Scholarship and is cosupervised with my colleague Pr. Emmanuel Beyou (IMP, Lyon).
• Ms. Magalie Schoumacker (PhD student 2022-2025), who is working on the development of new photoinitating systems for the synthesis of polymer latex particles using multiphoton absorption and NIR light in collaboration with Pr. Jacques Lalevée (IS2M, Mulhouse), Dr. Chantal Andraud, Cyrille Monnereau and Akos Banyasz (ENS Lyon) (ANR project : IR-EMULSION). Magalie will be cosupervised with my colleagues Dr. Muriel Lansalot and Dr. Emmanuel Lacôte (LHCEP, Lyon).
• Ms. Julie Bratanasu (PhD student, 2022-2025), who is working on the design of nanostructured, heat-deactivatable adhesives from vitrimer latex mixtures in the frame of the ANR VITRIPSA coordinated by Dr. Damien Montarnal (collaboration with SIMM (ESPCI) and ILM (Univ. Lyon1)).
• Ms. Lea Jacquin (PhD student, 2022-2025), is working on the synthesis of model polyethylene particles for the study of micro/nanoplastics in the oceans in the frame of the ANR POEM coordinated by Dr. Fabrice Brunel. Lea is cosupervised with Muriel Lansalot and Vincent Monteil.
• Ms. Qiuyi Hu (Master student, M2) will join our group in February 2022 to work on the design of nanocellulose-based particles and coatings.
• Mr. Paul Besson (Master student, M1) will study the durability of vanadium dioxide-based nanopowers for thermoactive coating applications in collaboration with EMSE (St Etienne).

Among my other current involvements, I am also partner of the ANR project POLYBORA coordinated by Dr. Jean Raynaud on the synthesis of 2D and 3D boron-containing functional polymer architectures.

 

Extra links :

Hal      Google Scholar      Research Gate       Publons

 

Keywords : 

Colloidal nanocomposite particles. Heterophase polymerizations. Pickering stabilization. Reversible deactivation radical polymerization. Polymerization induced self-assembly. Multi-responsive microgels. Functional (nano)materials. Kinetics and mechanism.