Modulating layer-by-layer assembled sodium alginate-chitosan film properties through incorporation of cellulose nanocrystals with different surface charge densities

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. Post-treatment 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. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’.

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Stimuli-responsive flexible membrane via co-assembling sodium alginate into assembly membranes of rod-like cellulose nanocrystals with an achiral array

Carbohydrate Polymers ◽

10.1016/j.carbpol.2021.117949 ◽

2021 ◽

Vol 262 ◽

pp. 117949

Author(s):

Xuhong Wang ◽

Na Feng ◽

Zhenxu Shi ◽

Na Zhou ◽

Jun Lu ◽

...

Keyword(s):

Sodium Alginate ◽

Cellulose Nanocrystals ◽

Stimuli Responsive ◽

Flexible Membrane

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The surface charge on manganese dioxides

Soil Research ◽

10.1071/sr9810041 ◽

1981 ◽

Vol 19 (1) ◽

pp. 41 ◽

Cited By ~ 67

Author(s):

RM McKenzie

Keyword(s):

Theoretical Model ◽

Surface Charge ◽

Charge Densities

Surface charge was measured on four synthetic manganese dioxides. Charge densities on two cryptomelanes followed closely the values predicted by a theoretical model. Charge densities on two birnessites were much higher, and did not fit the model.

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Preparation and properties of wet-spun microcomposite filaments from cellulose nanocrystals and alginate using a microfluidic device

BioResources ◽

10.15376/biores.16.3.5780-5793 ◽

2021 ◽

Vol 16 (3) ◽

pp. 5780-5793

Author(s):

Ji-Soo Park ◽

Chan-Woo Park ◽

Song-Yi Han ◽

Eun-Ah Lee ◽

Azelia Wulan Cindradewi ◽

...

Keyword(s):

Tensile Properties ◽

Sodium Alginate ◽

Calcium Chloride ◽

Microfluidic Device ◽

Cellulose Nanocrystals ◽

Average Diameter ◽

Coagulation Bath ◽

Al Content ◽

Orientation Index ◽

Cacl2 Solution

Cellulose nanocrystals (CNCs) were wet-spun in a coagulation bath for the fabrication of microfilaments, and the effect of sodium alginate (AL) addition on the wet-spinnability and properties of the microcomposite filament was investigated. The CNC suspension exhibited excellent wet-spinnability in calcium chloride (CaCl2) solution, and the addition of AL in CNC suspension resulted in the enhancement of the wet-spinnability of CNCs. As the AL content increased from 3% to 10%, the average diameter of the microcomposite filament decreased, and its tensile properties deteriorated. The increased spinning rate caused an increase in the orientation index of CNCs, resulting in an improvement in the tensile properties of the microcomposite filament.

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