Communication Dans Un Congrès Année : 2024

Chiral nematic nanocomposites with pitch gradient elaborated by ultrafiltration and ultraviolet curing of cellulose nanocrystal suspensions

Résumé

In this project we implement a new original methodology for manufacturing nano-composite films of anisotropic particles by ultrafiltration [1-3] and UV curing. The objective is to achieve control of the orientation and organization of anisotropic nanoparticles thanks to ultrafiltration process which induces a regular and simultaneous orientation and concentration over time of the nano-particles in the vicinity of the membrane. At the end of this filtration step, the concentrated structural organization is then fixed by UV curing. In order to master this new manufacturing process, we carry out in situ and ex situ characterizations at different scales by (WAXS, SAXS, SALS, and SEM). The structural properties (orientations, multi-scale organizations) are then linked to the functional properties (mechanical strength, hygrometry) measured on the composites developed. For optimized conditions of a poly(ethylene glycol) diacrylate (PEGDA) / cellulose nanocrystal (CNC) suspension, the application of transmembrane pressure enabled the CNCs to be structured and oriented within the PEGDA matrix, within the membrane surface during the ultrafiltration process. At the end of this filtration step UV curing under pressure has allowed to freeze the structural organization [4]. Structural analyses, via SAXS, WAXS and SEM, demonstrated that it is possible designing nanocomposite films with well-oriented and densely-packed CNCs, homogeneously distributed in a PEGDA matrix over a thickness of ca. 500 µm. For the first time cellulose nanocomposites with cholesteric structures and a pitch gradient have also been obtained [4]. The original hygromorphic properties and tensile mechanical properties of the nanocomposites were also characterized. This organization can serve as a basis for the development of thin films for photonics and hygrometric sensors. [1] - C. Rey et al., ACS Sust. Chem. Eng., 7, 10679-10689, (2019). https://doi.org/10.1021/acssuschemeng.9b01333 [2] - E.F. Semeraro et al., Colloids Surf. A, 584,124030, (2020). https://doi.org/10.1016/j.colsurfa.2019.124030 [3] - F. Pignon et al., J. Colloid Interface Sci., (2024). https://doi.org/10.1016/j.jcis.2023.12.164 [4] - S. Mandin et al., Carbohydrate Polymers, 337, 122162 (2024). https://doi.org/10.1016/j.carbpol.2024.122162

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Dates et versions

hal-04919292 , version 1 (29-01-2025)

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  • HAL Id : hal-04919292 , version 1

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Samuel Mandin, Lorenzo Metilli, Mohamed Karrouch, Christine Lancelon-Pin, Jean-Luc Putaux, et al.. Chiral nematic nanocomposites with pitch gradient elaborated by ultrafiltration and ultraviolet curing of cellulose nanocrystal suspensions. 1ère journées du GDR MultiPODE (Multifunctional nanostructured POlymer systems by DEsign), Sep 2024, Sophia Antipolis, France. ⟨hal-04919292⟩
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