An analysis on the electrophoretic mobility of cellulose nanocrystals as thin cylinders: relaxation and end effect

Lin, Kuan-Hsuan; Hu, Donghao; Sugimoto, Takashige; Chang, Feng-Cheng; Kobayashi, Motoyoshi; Enomae, Toshiharu

doi:10.1039/c9ra05156b

Cited by 12 publications

(10 citation statements)

References 25 publications

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“…59,60 In contrast, surface hydroxy groups on cellulose are not deprotonated (pK a > 12) and do not contribute to the CNC surface charge as degradation and/or mercerization would be expected under such conditions. 43,61 In general, electrophoretic mobility (typically reported as the ζ-potential for CNCs using the Smoluchowski approximation or, more recently, the modified Oshima−Overbeek equation 62 ) provides an indication of CNC suspension colloidal stability and may be more accessible/faster for industrial producers to assess CNC quality than titrations and elemental analysis. Particles with ζ-potentials above |10| mV are considered colloidally stable as there is sufficient electrostatic repulsion between particles to prevent aggregation.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Benchmarking Cellulose Nanocrystals Part II: New Industrially Produced Materials

et al. 2021

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The demand for industrially produced cellulose nanocrystals (CNCs) has been growing since 2012, when CelluForce Inc. opened its inaugural demonstration plant with a production capacity of 1 tonne per day. Currently, there are 10 industrial CNC producers worldwide, each producing a unique material. Thus, academic researchers and commercial users alike must consider the properties of all available CNCs and carefully select the material which will optimize the performance of their desired application. To support these efforts, this article presents a thorough characterization of four new industrially produced CNCs including sulfated CNCs from NORAM Engineering and Constructors Ltd. (in cooperation with InnoTech Alberta and Alberta-Pacific Forest Industries Inc.) and Melodea Ltd., as well as carboxylated CNCs from Anomera Inc. and Blue Goose Biorefineries Inc. These materials were benchmarked against typical lab-made, sulfated CNCs. While all CNCs were similar in size, shape, crystallinity, and suspension quality, the sulfated CNCs had a higher surface charge density than their carboxylated counterparts, leading to higher colloidal stability. Additionally, significant differences in the rheological profiles of aqueous CNC suspensions, as well as CNC thermal stability and self-assembly behavior, were observed. As such, this article highlights both the subtle and significant differences between five CNC types and acts as a guide for end-users looking to optimize the performance of CNC-based materials.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Benchmarking Cellulose Nanocrystals Part II: New Industrially Produced Materials

et al. 2021

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“…Apparent ζ-potentials and electrophoretic mobilities were −56 mV and −4.41 μmcm/Vs, respectively, at pH 7 and −44 mV and −3.45 μmcm/Vs, respectively, at pH 4 ( Figure S5 ), facilitating the stability of the CNCs in aqueous dispersions. 62 The sulfate content was determined by conductometric titration to be 239 μmol/g ( Figure S6 ). To form homogeneous aqueous mixtures with CNCs, we used an initially neutral random terpolymer PDEGMA 417 - rnd -POEGMA 109 - rnd -PNBOCAEMA 54 consisting of photocleavable NBOCAEMA repeat units and DEGMA and OEGMA repeat units, allowing LCST behavior.…”

Section: Resultsmentioning

confidence: 99%

UV-Triggered On-Demand Temperature-Responsive Reversible and Irreversible Gelation of Cellulose Nanocrystals

et al. 2020

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We show ionically cross-linked, temperature-responsive reversible or irreversible hydrogels of anionic cellulose nanocrystals (CNCs) and methacrylate terpolymers by mixing them homogeneously in the initially charge-neutral state of the polymer, which was subsequently switched to be cationic by cleaving side groups by UV irradiation. The polymer is a random terpolymer poly(di(ethylene glycol) methyl ether methacrylate)- rnd -poly(oligo(ethylene glycol) methyl ether methacrylate)- rnd -poly(2-((2-nitrobenzyl)oxycarbonyl)aminoethyl methacrylate), that is, PDEGMA- rnd -POEGMA- rnd -PNBOCAEMA. The PDEGMA and POEGMA repeating units lead to a lower critical solution temperature (LCST) behavior. Initially, homogeneous aqueous mixtures are obtained with CNCs, and no gelation is observed even upon heating to 60 °C. However, upon UV irradiation, the NBOCAEMAs are transformed to cationic 2-aminoethyl methacrylate (AEMA) groups, as 2-nitrobenzaldehyde moieties are cleaved. The resulting mixtures of anionic CNC and cationic PDEGMA- rnd -POEGMA- rnd -PAEMA show gelation for sufficiently high polymer fractions upon heating to 60 °C due to the interplay of ionic interactions and LCST. For short heating times, the gelation is thermoreversible, whereas for long enough heating times, irreversible gels can be obtained, indicating importance of kinetic aspects. The ionic nature of the cross-linking is directly shown by adding NaCl, which leads to gel melting. In conclusion, the optical triggering of the polymer ionic interactions in combination with its LCST phase behavior allows a new way for ionic nanocellulose hydrogel assemblies.

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“…One may be aware that these results are accurate providing a clear suspension, with a suitable concentration and is a surface charge dependent measurement [13] . In addition, it may be more challenging compared to other nanoparticles to use usual models (ex: Smoluchowski's equation) because of the double layer relaxation and end effect of CNC [14] . Beyond surface charge, hydrolysis conditions (temperature, time, concentration) also impact the particle size [15] , [16] , [17] .…”

Section: Introductionmentioning

confidence: 99%

Evidence-based guidelines for the ultrasonic dispersion of cellulose nanocrystals

Girard

Vidal

Bertrand

et al. 2021

Ultrasonics Sonochemistry

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An analysis on the electrophoretic mobility of cellulose nanocrystals as thin cylinders: relaxation and end effect

Abstract: Cellulose nanocrystals (CNCs) are extracted from cellulosic fibers via sulfuric acid hydrolysis and found to exhibit unique properties due to their nanoscale, ordered structure, and surface morphology.

Cited by 12 publications

References 25 publications

Benchmarking Cellulose Nanocrystals Part II: New Industrially Produced Materials

Benchmarking Cellulose Nanocrystals Part II: New Industrially Produced Materials

UV-Triggered On-Demand Temperature-Responsive Reversible and Irreversible Gelation of Cellulose Nanocrystals

Evidence-based guidelines for the ultrasonic dispersion of cellulose nanocrystals

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