Ultrathin multilayer films, assembled by the layer-by-layer (LbL) technique, are recently attracting more interest due to the simple way of their preparation and to their different possible coatings applications (optics, electrics, biosensors�) [C. Cerclier et al. (2011). Advanced Materials, 23  , 3791-3795]. In this framework, thin multilayer films were successfully prepared using TEMPO-oxidized cellulose nanofibrils (CNF) as an anionic polyelectrolyte and poly-(allylamine hydrochloride) (PAH) as a cationic one. The aim of this work was to control the architecture of these films in order to obtain materials with tunable properties. The key-parameter we used in the construction process was the ionic strength. Adding salt to PAH solution (1M) caused a change in the polymer conformation which influences directly the thickness increment per bilayer of the films [C. Moreau et al. (2012). Langmuir, 28 , 10425-10436], while adding small amount of salt to the NFC suspension caused a slight aggregation of the nanoparticles that modifies the architecture of the films as seen by atomic force microscopy. The change in architecture is accompanied by a modification of the films porosity showed by neutron reflectivity experiments. Finally, the impact of the architecture on the films optical properties was evaluated by light transmittance measurements (See Fig. 1).Figure 1.   UV-Vis light transmittance of original quartz substrate and NFC-PAH LbL coated quartz substrate, at different bilayer number and different salt concentration in PAH solution

Tuning optical properties of cellulose nanofibrils-based multilayered thin films

247th National Meeting (2014)

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