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Wim Thielemans - One of the best experts on this subject based on the ideXlab platform.
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One-pot functionalization of Cellulose Nanocrystals with various cationic groups
Cellulose, 2016Co-Authors: Latifah Jasmani, Samuel Eyley, Christina Schütz, Hans Van Gorp, Steven De Feyter, Wim ThielemansAbstract:After successful cationization of Cellulose Nanocrystals (CNCs) to produce pyridinium-grafted-CNCs, a variety of different cationic CNCs were prepared using a similar procedure, thus unlocking access to a wide variety of cationized Cellulose Nanocrystals through a simple one-pot reaction. In this study, cationic CNCs were prepared through the use of 4-(1-bromoethyl)benzoic acid or 4-bromomethylbenzoic acid, p -toluenesulfonyl chloride, CNCs, and two different amines, 1-methylimidazole and 4-dimethylaminopyridine. The amines acted as both the base catalyst for the esterification and the nucleophile to form the cationic charge. This method offers a versatile and straightforward route to prepare a variety of different cationic Nanocrystals and therefore tailor their interaction with their environment.
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CO2 controlled flocculation of microalgae using pH responsive Cellulose Nanocrystals
Nanoscale, 2015Co-Authors: Samuel Eyley, Dries Vandamme, Sanjaya Lama, Guy Van Den Mooter, Koenraad Muylaert, Wim ThielemansAbstract:Cellulose Nanocrystals were grafted with imidazole functionalities up to DS 0.06 using a one-pot functionalization strategy. The resulting Nanocrystals were shown to have a pH responsive surface charge which was found to be positive below pH 6 and negative above pH 7. These imidazolyl Cellulose Nanocrystals were tested for flocculation of Chlorella vulgaris using CO2 to induce flocculation. Up to 90% flocculation efficiency was achieved with 200 mg L(-1) dose. Furthermore, the modified Cellulose Nanocrystals showed good compatibility with the microalgae during cultivation, giving potential for the production of reversible flocculation systems.
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Surface modification of Cellulose Nanocrystals.
Nanoscale, 2014Co-Authors: Samuel Eyley, Wim ThielemansAbstract:Chemical modification of Cellulose Nanocrystals is an increasingly popular topic in the literature. This review analyses the type of Cellulose nanocrystal modification reactions that have been published in the literature thus far and looks at the steps that have been taken towards analysing the products of the nanocrystal modifications. The main categories of reactions carried out on Cellulose Nanocrystals are oxidations, esterifications, amidations, carbamations and etherifications. More recently nucleophilic substitutions have been used to introduce more complex functionality to Cellulose Nanocrystals. Multi-step modifications are also considered. This review emphasizes quantification of modification at the nanocrystal surface in terms of degree of substitution and the validity of conclusions drawn from different analysis techniques in this area. The mechanisms of the modification reactions are presented and considered with respect to the effect on the outcome of the reactions. While great strides have been made in the quality of analytical data published in the field of Cellulose nanocrystal modification, there is still vast scope for improvement, both in data quality and the quality of analysis of data. Given the difficulty of surface analysis, cross-checking of results from different analysis techniques is fundamental for the development of reliable Cellulose nanocrystal modification techniques.
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A facile one-pot route to cationic Cellulose Nanocrystals.
Nanoscale, 2013Co-Authors: Latifah Jasmani, Samuel Eyley, Rachel Wallbridge, Wim ThielemansAbstract:Pyridinium-grafted-Cellulose Nanocrystals were prepared by a simple one-pot reaction using 4-(1-bromoethyl/bromomethyl)benzoic acid, pyridine and Cellulose Nanocrystals (CNCs). The grafting consists of an esterification reaction between 4-(1-bromoethyl/bromomethyl)benzoic acid and CNCs and a nucleophilic attack on the C–Br bond of 4-(1-bromoethyl/bromomethyl)benzoic acid by pyridine. This reaction simplifies existing cationization methods, which leads to a higher grafting density while retaining the CNC crystallinity.
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imidazolium grafted Cellulose Nanocrystals for ion exchange applications
Chemical Communications, 2011Co-Authors: Samuel Eyley, Wim ThielemansAbstract:An imidazolium salt was grafted to Cellulose Nanocrystals (also called nanowhiskers) using copper(I) catalysed azide–alkyne cycloaddition and the bromide anion was successfully exchanged for bistriflimide and an anionic dye, providing the opportunity to synthesize a wide variety of ion exchange systems or catalysts using Cellulose Nanocrystals as a support medium.
Samuel Eyley - One of the best experts on this subject based on the ideXlab platform.
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One-pot functionalization of Cellulose Nanocrystals with various cationic groups
Cellulose, 2016Co-Authors: Latifah Jasmani, Samuel Eyley, Christina Schütz, Hans Van Gorp, Steven De Feyter, Wim ThielemansAbstract:After successful cationization of Cellulose Nanocrystals (CNCs) to produce pyridinium-grafted-CNCs, a variety of different cationic CNCs were prepared using a similar procedure, thus unlocking access to a wide variety of cationized Cellulose Nanocrystals through a simple one-pot reaction. In this study, cationic CNCs were prepared through the use of 4-(1-bromoethyl)benzoic acid or 4-bromomethylbenzoic acid, p -toluenesulfonyl chloride, CNCs, and two different amines, 1-methylimidazole and 4-dimethylaminopyridine. The amines acted as both the base catalyst for the esterification and the nucleophile to form the cationic charge. This method offers a versatile and straightforward route to prepare a variety of different cationic Nanocrystals and therefore tailor their interaction with their environment.
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CO2 controlled flocculation of microalgae using pH responsive Cellulose Nanocrystals
Nanoscale, 2015Co-Authors: Samuel Eyley, Dries Vandamme, Sanjaya Lama, Guy Van Den Mooter, Koenraad Muylaert, Wim ThielemansAbstract:Cellulose Nanocrystals were grafted with imidazole functionalities up to DS 0.06 using a one-pot functionalization strategy. The resulting Nanocrystals were shown to have a pH responsive surface charge which was found to be positive below pH 6 and negative above pH 7. These imidazolyl Cellulose Nanocrystals were tested for flocculation of Chlorella vulgaris using CO2 to induce flocculation. Up to 90% flocculation efficiency was achieved with 200 mg L(-1) dose. Furthermore, the modified Cellulose Nanocrystals showed good compatibility with the microalgae during cultivation, giving potential for the production of reversible flocculation systems.
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Surface modification of Cellulose Nanocrystals.
Nanoscale, 2014Co-Authors: Samuel Eyley, Wim ThielemansAbstract:Chemical modification of Cellulose Nanocrystals is an increasingly popular topic in the literature. This review analyses the type of Cellulose nanocrystal modification reactions that have been published in the literature thus far and looks at the steps that have been taken towards analysing the products of the nanocrystal modifications. The main categories of reactions carried out on Cellulose Nanocrystals are oxidations, esterifications, amidations, carbamations and etherifications. More recently nucleophilic substitutions have been used to introduce more complex functionality to Cellulose Nanocrystals. Multi-step modifications are also considered. This review emphasizes quantification of modification at the nanocrystal surface in terms of degree of substitution and the validity of conclusions drawn from different analysis techniques in this area. The mechanisms of the modification reactions are presented and considered with respect to the effect on the outcome of the reactions. While great strides have been made in the quality of analytical data published in the field of Cellulose nanocrystal modification, there is still vast scope for improvement, both in data quality and the quality of analysis of data. Given the difficulty of surface analysis, cross-checking of results from different analysis techniques is fundamental for the development of reliable Cellulose nanocrystal modification techniques.
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A facile one-pot route to cationic Cellulose Nanocrystals.
Nanoscale, 2013Co-Authors: Latifah Jasmani, Samuel Eyley, Rachel Wallbridge, Wim ThielemansAbstract:Pyridinium-grafted-Cellulose Nanocrystals were prepared by a simple one-pot reaction using 4-(1-bromoethyl/bromomethyl)benzoic acid, pyridine and Cellulose Nanocrystals (CNCs). The grafting consists of an esterification reaction between 4-(1-bromoethyl/bromomethyl)benzoic acid and CNCs and a nucleophilic attack on the C–Br bond of 4-(1-bromoethyl/bromomethyl)benzoic acid by pyridine. This reaction simplifies existing cationization methods, which leads to a higher grafting density while retaining the CNC crystallinity.
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imidazolium grafted Cellulose Nanocrystals for ion exchange applications
Chemical Communications, 2011Co-Authors: Samuel Eyley, Wim ThielemansAbstract:An imidazolium salt was grafted to Cellulose Nanocrystals (also called nanowhiskers) using copper(I) catalysed azide–alkyne cycloaddition and the bromide anion was successfully exchanged for bistriflimide and an anionic dye, providing the opportunity to synthesize a wide variety of ion exchange systems or catalysts using Cellulose Nanocrystals as a support medium.
Emily D. Cranston - One of the best experts on this subject based on the ideXlab platform.
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Production routes to tailor the performance of Cellulose Nanocrystals
Nature Reviews Materials, 2021Co-Authors: Oriana M. Vanderfleet, Emily D. CranstonAbstract:Cellulose Nanocrystals (CNCs) are bio-based, high aspect ratio nanoparticles that are industrially produced in tonne-per-day quantities across the globe. CNCs can be used to improve the performance of a large range of materials such as emulsions and foams, biomedical devices, electronics and sensors, high-viscosity fluids and polymer composites. Their ability to do so, however, is highly dependent on the way they are produced. In this Review, we assess the properties of CNCs from more than 30 production routes and 40 biomass sources to help CNC users select the right material for their desired application. CNCs produced by various methods are evaluated against three target properties: colloidal stability, size and crystallinity index. Alternative production routes and/or starting materials are suggested to overcome challenges associated with CNC use, including increasing compatibility with hydrophobic materials, resistance to thermal degradation and colloidal stability in high ionic strength environments. Additionally, we discuss industrial production of CNCs, as well as considerations for increasing the yield and reducing the environmental impact of these processes. Overall, this Review guides researchers and CNC users towards a deeper understanding of how production processes can be modified to control CNC properties and subsequently tailor their performance. Cellulose Nanocrystals are rigid rod-shaped nanoparticles that show promise as additives in composites, emulsions, foams and biomedical devices and as rheological modifiers. In this Review, the authors guide end users towards selecting Cellulose sources and production routes that optimize the performance of Cellulose Nanocrystals in their intended application.
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Correction: Cationic surface functionalization of Cellulose Nanocrystals
Soft Matter, 2015Co-Authors: Merima Hasani, Gunnar Westman, Emily D. Cranston, Derek G. GrayAbstract:Correction for ‘Cationic surface functionalization of Cellulose Nanocrystals’ by Merima Hasani et al., Soft Matter, 2008, 4, 2238–2244.
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polymer grafted Cellulose Nanocrystals as ph responsive reversible flocculants
Biomacromolecules, 2013Co-Authors: Jian Li, Kushlani Wijesekera, Emily D. CranstonAbstract:Cellulose Nanocrystals (CNCs) are a sustainable nanomaterial with applications spanning composites, coatings, gels, and foams. Surface modification routes to optimize CNC interfacial compatibility and functionality are required to exploit the full potential of this material in the design of new products. In this work, CNCs have been rendered pH-responsive by surface-initiated graft polymerization of 4-vinylpyridine with the initiator ceric(IV) ammonium nitrate. The polymerization is a one-pot, water-based synthesis carried out under sonication, which ensures even dispersion of the Cellulose Nanocrystals during the reaction. The resultant suspensions of poly(4-vinylpyridine)-grafted Cellulose Nanocrystals (P4VP-g-CNCs) show reversible flocculation and sedimentation with changes in pH; the loss of colloidal stability is visible by eye even at concentrations as low as 0.004 wt %. The presence of grafted polymer and the ability to tune the hydrophilic/hydrophobic properties of P4VP-g-CNCs were characterized b...
Vijay Kumar Thakur - One of the best experts on this subject based on the ideXlab platform.
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Recent progress in Cellulose Nanocrystals: sources and production
Nanoscale, 2017Co-Authors: Djalal Trache, M. K.mohamad Haafiz, M Hazwan Hussin, Vijay Kumar ThakurAbstract:Cellulose Nanocrystals, a class of fascinating bio-based nanoscale materials, have received a tremendous amt. of interest both in industry and academia owing to its unique structural features and impressive physicochem. properties such as biocompatibility, biodegradability, renewability, low d., adaptable surface chem., optical transparency, and improved mech. properties. This nanomaterial is a promising candidate for applications in fields such as biomedical, pharmaceuticals, electronics, barrier films, nanocomposites, membranes, supercapacitors, etc. New resources, new extn. procedures, and new treatments are currently under development to satisfy the increasing demand of manufg. new types of Cellulose Nanocrystals-based materials on an industrial scale. Therefore, this review addresses the recent progress in the prodn. methodologies of Cellulose Nanocrystals, covering principal Cellulose resources and the main processes used for its isolation. A crit. and anal. examn. of the shortcomings of various approaches employed so far is made. Addnl., structural organization of Cellulose and nomenclature of Cellulose nanomaterials have also been discussed for beginners in this field. [on SciFinder(R)]
Pierre Krausz - One of the best experts on this subject based on the ideXlab platform.
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Antimicrobial silver nanoparticles generated on Cellulose Nanocrystals
Journal of Nanoparticle Research, 2011Co-Authors: Nicolas Drogat, Robert Granet, Vincent Sol, Abdelmajid Memmi, Naïma Saad, Carmen Klein Koerkamp, Philippe Bressollier, Pierre KrauszAbstract:We describe a new approach to the formation of silver nanoparticles (Ag NPs) using Cellulose Nanocrystals. The process involves periodate oxidation of Cellulose Nanocrystals, generating aldehyde functions which, in turn, are used to reduce Ag+ into Ag0 in mild alkaline conditions. The nanoparticles were characterized using transmission electron microscopy (TEM) and ultraviolet-visible absorption spectroscopy. From the microscope studies (TEM) we observed that Ag NPs have spherical shape with a size distribution comprise between 20 and 45 nm. The antibacterial activity was assessed using the minimum inhibitory concentration. The antibacterial assays compare favourably with most of other experiments conducted with the same species.