Modulation of Cellulose Nanocrystals Amphiphilic Properties to Stabilize Oil/Water Interface

Kalashnikova, Irina; Bizot, Hervé; Cathala, Bernard; Capron, Isabelle

doi:10.1021/bm201599j

Cited by 517 publications

(477 citation statements)

References 40 publications

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“…at molecular contact 3.7 nm. Such a surface density is in agreement with values found in the literature (Kalashnikova et al 2012 be found, as experimentally determined here. The long-ranged electrostatic repulsion increased in the following order 50 mM NaCl \ 5 mM CaCl 2 \ 0.2 mM AlCl 3 , and for the short-ranged electrostatic repulsion, we found the opposite behavior.…”

Section: Monte Carlo Simulationssupporting

confidence: 93%

Aggregation behavior of aqueous cellulose nanocrystals: the effect of inorganic salts

et al. 2016

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Natural anisotropic building-blocks such as cellulose nanocrystals (CNCs) have attracted considerable attention due to their biodegradability and nanometer-size. In this work the colloidal behavior of CNCs, obtained from sulfuric acid hydrolysis of microcrystalline cellulose, has been studied in presence of salts of different valences. The influence on the colloidal stability and nature of aggregates has been investigated for monovalent salts (LiCl, NaCl, KCl, CsCl), divalent salts (CaCl 2 and MgCl 2 ), and a trivalent salt (AlCl 3 ), both experimentally by means of turbidity and small angle X-ray scattering (SAXS) measurements, as well as by Monte Carlo simulations using a simple coarse-grained model. For the entire salt series, a critical aggregation concentration (CAC) could be determined by turbidity measurements, as a result of the reduction of effective Coulomb repulsions due to the presence of sulfate groups on the CNC surface. The CACs also followed the Schulze-Hardy law, i.e. the critical aggregation concentration decreased with increasing counterion valence. For the monovalent ions, the CACs followed the trend, which could be rationalized in terms of matching affinities between the cation and the sulfate groups present at the surface of CNCs. From the SAXS measurements it was shown that the density of the aggregates increased with increasing salt concentration and ion valence. In addition, these findings were rationalized by means of simulation, which showed a good correlation with experimental data. The combination of the experimental techniques and the simulations offered insight into interactionaggregation relationship of CNC suspensions, which is of importance for their structural design applications.Electronic supplementary material The online version of this article

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Section: Monte Carlo Simulationssupporting

confidence: 93%

Aggregation behavior of aqueous cellulose nanocrystals: the effect of inorganic salts

et al. 2016

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“…Besides, the less charged holoCNCs could also shift toward stronger inter holoCNC association and away from hydrophilic interaction with water to stabilize the O/W interfaces, as highly charged CNCs have been known to reversibly desorb from the oil/ water interface, except when the negative charge groups are removed by desulfation or screened by increasing ionic strength. 55,56 The hydrodynamic diameters of the emulsion droplets in holoCNCs stabilized emulsions were 1.2−1.6 μm, double in sizes (0.6−0.8 μm) of those in CNC stabilized emulsions (Figure 4b). The significantly larger hydrodynamic diameters of emulsion droplets stabilized with holoCNCs are further proof to their greater hydrophobicity to stabilize more oil.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Holocellulose Nanocrystals: Amphiphilicity, Oil/Water Emulsion, and Self-Assembly

Jiang

Hsieh

2015

Biomacromolecules

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Amphiphilic holoCNCs were derived from rice straw holocellulose by sulfuric acid hydrolysis (64%, 45 °C, 45 min) at 11.6% yield (8.8% of rice straw). HoloCNCs are similar in lateral dimensions (4.1 ± 1.6 nm thick, 6.4 ± 1.8 nm wide), but shorter and more heterogeneous in lengths (113 ± 70 nm long), less negatively charged (0.128 mmol/g) and less crystalline (CrI 84.4%) than CNCs. HoloCNCs were also more thermally stable (T max =284 °C), attributed to the presence of residual lignosulfonate, hemicellulose, and silica. Most remarkable, the amphiphilic holoCNCs were more hydrophobic than CNCs, exhibiting distinct surface active behaviors and lowering equilibrium surface tension to 49.2 mN/m at above 0.57% critical aggregation concentration. HoloCNCs not only stabilize 30% more oil-in-water (O/W) emulsion and formed droplets (1.2−1.6 μm) doubled the sizes of those with CNCs, but also self-assembled into highly mesoporous structures with up to 3× higher specific surface (111 m 2 /g) and total pore volume (0.40 cm 3 /g) than that from CNCs upon freeze-drying. The unique surface active, amphiphilic, and less self-assembling properties of holoCNCs offer new desirable characteristics but without additional isolation process nor surface modification of CNCs.

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“…CNCs have recently been used as emulsion stabilizers by taking advantage of their selfassembling ability at the oil-water interface, similar to particle-stabilized Pickering systems [16,17]. They thus lead to the formation of ultrastable and monodispersed oil-in-water emulsions.…”

Section: Introductionmentioning

confidence: 99%

Some modification of cellulose nanocrystals for functional Pickering emulsions

Saidane¹,

Perrin²,

Cherhal³

et al. 2016

Phil. Trans. R. Soc. A.

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Cellulose nanocrystals (CNCs) are negatively charged colloidal particles well known to form highly stable surfactant-free Pickering emulsions. These particles can vary in surface charge density depending on their preparation by acid hydrolysis or applying post-treatments. CNCs with three different surface charge densities were prepared corresponding to 0.08, 0.16 and 0.64 e nm −2 , respectively. Posttreatment might also increase the surface charge density. The well-known TEMPO-mediated oxidation substitutes C 6 -hydroxyl groups by C 6 -carboxyl groups on the surface. We report that these different modified CNCs lead to stable oil-in-water emulsions. TEMPO-oxidized CNC might be the basis of further modifications. It is shown that they can, for example, lead to hydrophobic CNCs with a simple method using quaternary ammonium salts that allow producing inverse water-in-oil emulsions. Different from CNC modification before emulsification, modification can be carried out on the droplets after emulsification. This way allows preparing functional capsules according to the layer-by-layer process. As a result, it is demonstrated here the large range of use of these biobased rod-like nanoparticles, extending therefore their potential use to highly sophisticated formulations.

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Modulation of Cellulose Nanocrystals Amphiphilic Properties to Stabilize Oil/Water Interface

Cited by 517 publications

References 40 publications

Aggregation behavior of aqueous cellulose nanocrystals: the effect of inorganic salts

Aggregation behavior of aqueous cellulose nanocrystals: the effect of inorganic salts

Holocellulose Nanocrystals: Amphiphilicity, Oil/Water Emulsion, and Self-Assembly

Some modification of cellulose nanocrystals for functional Pickering emulsions

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