Reversible modification of structure and properties of cellulose nanofibril-based multilayered thin films induced by postassembly acid treatment.

A postassembly acid-treatment consisting of an immersion in 5 mM HCl solution was applied to carboxylated cellulose nanofibrils (CNF)-poly(allylamine) hydrochloride (PAH) multilayered thin films. Our results show that the treatment did not affect the overall thickness of the films without any loss of the components. However, a modification of the surface morphology was observed, as well as the swelling behavior.

Chitin nanocrystals for Pickering high internal phase emulsions.

Chitin is a natural polymer of glucosamine bearing N-acetyl groups. Chitin nanocrystals (ChiNCs), resulting from the acid hydrolysis of amorphous regions of chitin, are crystalline positively charged rod-like particles. ChiNCs show some interfacial properties and very efficiently stabilize oil/water interfaces, leading to the so-called Pickering emulsions.

Cellulose nanofibril-based multilayered thin films: effect of ionic strength on porosity, swelling, and optical properties.

TEMPO-oxidized cellulose nanofibrils (CNF) and synthetic poly(allylamine) hydrochloride (PAH) were used to build multilayered thin films via the dipping-assisted layer-by-layer technique. We used the ionic strength, in both CNF suspension and PAH solution, as a key parameter to control the structure of the films. Three systems with different ionic strength parameters were investigated.

Cellulose nanocrystal-assisted dispersion of luminescent single-walled carbon nanotubes for layer-by-layer assembled hybrid thin films.

Highly stable single-walled carbon nanotube (SWNT) dispersions are obtained after ultrasonication in cellulose nanocrystal (CN) aqueous colloidal suspensions. Mild dispersion conditions were applied to preserve the SWNT length in order to facilitate the identification of hybrid objects. This led to a moderate dispersion of 24% of the SWNTs.

Modulation of cellulose nanocrystals amphiphilic properties to stabilize oil/water interface.

Neutral cellulose nanocrystals dispersed in water were shown in a previous work to stabilize oil/water interfaces and produce Pickering emulsions with outstanding stability, whereas sulfated nanocrystals obtained from cotton did not show interfacial properties. To develop a better understanding of the stabilization mechanism, amphiphilic properties of the nanocrystals were modulated by tuning the surface charge density to investigate emulsifying capability on two sources of cellulose: cotton linters (CCN) and bacterial cellulose (BCN). This charge adjustment made it possible to determine the conditions where a low surface charge density, below 0.

New Pickering emulsions stabilized by bacterial cellulose nanocrystals.

We studied oil in water Pickering emulsions stabilized by cellulose nanocrystals obtained by hydrochloric acid hydrolysis of bacterial cellulose. The resulting solid particles, called bacterial cellulose nanocrystals (BCNs), present an elongated shape and low surface charge density, forming a colloidal suspension in water. The BCNs produced proved to stabilize the hexadecane/water interface, promoting monodispersed oil in water droplets around 4 μm in diameter stable for several months.

Improved colloidal stability of bacterial cellulose nanocrystal suspensions for the elaboration of spin-coated cellulose-based model surfaces.

Well-dispersed suspensions are a prerequisite when preparing smooth model surfaces based on neutral bacterial cellulose nanocrystals (BCNs). However, neutral nanocrystal suspensions present pronounced particle aggregation. Carboxymethyl cellulose (CMC) or xyloglucan (XG) was therefore added to aggregated BCN suspensions.

Elaboration of spin-coated cellulose-xyloglucan multilayered thin films.

In the context of developing a biomimetic model of the primary cell wall, our aim was to produce multilayered thin films composed of cellulose nanocrystals (CN) and xyloglucan (XG). We investigated the effect of XG concentrations ranging from 0.5 g/L to 10 g/L.

Enthalpic studies of xyloglucan-cellulose interactions.

We report a study of xyloglucan (XG)-cellulose interactions made possible by the preparation of various well-defined cellulosic and xyloglucosidic substrates. Bacterial microcrystalline cellulose (BMCC) as well as cellulose whiskers (CellWhisk) were used as cellulosic substrates. Xyloglucosidic substrates were obtained from Rubus cells and Tamarindus indica seeds.