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Ndizeye, Natacha
Publications (5 of 5) Show all publications
Suriyanarayanan, S., Olsson, G. D., Kathiravan, S., Ndizeye, N. & Nicholls, I. A. (2019). Non-Ionic Deep Eutectic Liquids: Acetamide-Urea Derived Room Temperature Solvents. International Journal of Molecular Sciences, 20(12), Article ID 2857.
Open this publication in new window or tab >>Non-Ionic Deep Eutectic Liquids: Acetamide-Urea Derived Room Temperature Solvents
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2019 (English)In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 20, no 12, article id 2857Article in journal (Refereed) Published
Abstract [en]

A family of non-ionic deep eutectic liquids has been developed based upon mixtures of solid N-alkyl derivatives of urea and acetamide that in some cases have melting points below room temperature. The eutectic behaviour and physical characteristics of a series of eleven eutectic mixtures are presented, along with a molecular dynamics study-supported hypothesis for the origin of the non-ideal mixing of these substances. Their use as solvents in applications ranging from natural product extraction to organic and polymer synthesis are demonstrated.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
deep-eutectic solvent, flickering cluster, acetamide-urea
National Category
Organic Chemistry
Research subject
Chemistry, Organic Chemistry
Identifiers
urn:nbn:se:lnu:diva-86961 (URN)10.3390/ijms20122857 (DOI)000473756000007 ()31212745 (PubMedID)2-s2.0-85068473566 (Scopus ID)
Available from: 2019-07-23 Created: 2019-07-23 Last updated: 2019-08-29Bibliographically approved
Ndizeye, N., Suriyanarayanan, S. & Nicholls, I. A. (2019). Polymer synthesis in non-ionic deep eutectic solvents. Polymer Chemistry, 10(39), 5289-5295
Open this publication in new window or tab >>Polymer synthesis in non-ionic deep eutectic solvents
2019 (English)In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 10, no 39, p. 5289-5295Article in journal (Refereed) Published
Abstract [en]

Herein, we report the use of the use of non-ionic deep eutectic solvents (ni-DESs) as porogens in polymer synthesis. Three ni-DES systems, acetamide-N-methylacetamide (AA-NMA), N-methylacetamide-N-methylurea (NMA-NMU) and N-methylacetamide-N,N'-dimethylurea (NMA-NN'DMU), were deployed in the synthesis of a series of cross-linked copolymer monoliths comprised of a functional monomer, methacrylic acid (MAA) or hydroxyethylmethacrylate (HEMA), and a cross-linking monomer, ethylene glycol dimethylacrylate (EGDMA) or divinylbenzene (DVB) or 1,4-bis(acryloyl)piperazine (BAP). Polymers were synthesized under thermally initiated conditions with 2,2'-azobis(2-methylpropionitrile) (AIBN) or 2,2'-azobis(2-amidinopropane) dihydrochloride (ABAH) as an initiator. The resulting polymer monoliths were ground and sieved to yield particles of 63-125 mu m. Corresponding polymers prepared in conventional porogens, acetonitrile, toluene and water were synthesized to serve as controls. The influence of the respective niDESs on polymer morphologies was examined by Brunauer-Emmett-Teller (BET) N2-adsorption, Fourier transform infrared spectroscopy (FT-IR), elemental analysis, scanning electron microscopy (SEM) and zeta potential measurements. The materials displayed surface areas, pore volumes and pore diameters of 115-532 m(2) g(-1), 0.1-1.4 cm(3) g(-1) and 5.2-12.5 nm, generally comparable with those of polymers obtained using conventional solvents, thus presenting these ni-DESs as viable alternatives to conventional organic solvents. The post-polymerization recovery of the ni-DESs (>80%) was demonstrated, highlighting the potential for using these novel liquids as alternatives to conventional, and often more expensive, toxic, flammable or volatile solvents in polymer synthesis.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Polymer Chemistry
Research subject
Chemistry, Organic Chemistry
Identifiers
urn:nbn:se:lnu:diva-89808 (URN)10.1039/c9py01039d (DOI)000489265500013 ()
Available from: 2019-10-25 Created: 2019-10-25 Last updated: 2019-10-25Bibliographically approved
Ndizeye, N., Suriyanarayanan, S. & Nicholls, I. A. (2018). Hierarchical polymeric architectures through molecular imprinting in liquid crystalline environments. European Polymer Journal, 106, 223-231
Open this publication in new window or tab >>Hierarchical polymeric architectures through molecular imprinting in liquid crystalline environments
2018 (English)In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 106, p. 223-231Article in journal (Refereed) Published
Abstract [en]

The use of liquid crystalline (LC) media as sacrificial templates during the polymer synthesis has been explored. The LC-media introduce morphological features into resultant polymers which when used together with molecular imprinting can produce materials with hierarchical architectures. Bupivacaine (1) imprinted co-polymers of 2-hydroxyethylmethacrylate (HEMA) (2a) and 1,4-divinylbenzene (DVB) (3a) were synthesized using photochemical initiation in lyotrophic liquid crystalline phases of AOT (5) in water/p-xylene and Triton X-100 (6) /water systems. SEM studies revealed the impact of the LC-media on polymer morphology, with polymer brush-like structures, with bristles of ≈30 nm diameter. The polymer morphology reflects that of the hexagonal phase of the LC medium. The rebinding characteristics of polymer films were evaluated quartz crystal microbalance (QCM, under FIA conditions). The influence of the presence of imprinting-derived recognition sites in AOT (5) in water/p-xylene polymer film induced brush-like features which provided a 25-fold enhancement of sensor sensitivity. This chemosensor was shown to be selective for the local anesthetic template, bupivacaine, through studies using the structural analogues ropivacaine and mepivacaine.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Bupivacaine, liquid crystalline medium, molecularly imprinted polymer, nanostructured polymer films, piezoelectric sensor, quartz crystal microbalance
National Category
Polymer Chemistry
Research subject
Chemistry, Organic Chemistry
Identifiers
urn:nbn:se:lnu:diva-78287 (URN)10.1016/j.eurpolymj.2018.07.036 (DOI)000445993400027 ()2-s2.0-85050408593 (Scopus ID)
Available from: 2018-10-11 Created: 2018-10-11 Last updated: 2019-08-29Bibliographically approved
Ndizeye, N. (2018). New Strategies for Preparing Polymers with Hierarchical Architectures. (Doctoral dissertation). Växjö: Linnaeus University Press
Open this publication in new window or tab >>New Strategies for Preparing Polymers with Hierarchical Architectures
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The objective of this thesis was to explore novel approaches for controlling morphologies and molecular recognition behaviour of polymers and to use these strategies in conjunction with the molecular imprinting technique in order to either enhance polymer performance in quartz crystal microbalance (QCM) sensor applications, or as an alternative to conventional solvents of polymerization. In Papers I and II, the use of liquid crystalline media in the synthesis of molecularly imprinted polymers was demonstrated. When used in conjunction with the molecular imprinting technique the LC media induced hierarchical material architectures, which provided an enhancement of QCM-sensor sensitivity. The use of a class of novel solvents, so-called “non-ionic deep eutectic solvents (ni-DESs)”, was explored in polymer synthesis, Paper III, and for molecularly imprinted polymer synthesis, Paper IV. The use of these solvents produced polymers with morphological features comparable to those prepared in conventional solvents, and sensitivities towards bupivacaine template were observed. Collectively these results present a new strategy for generating new hierarchical polymer architectures and a new class of solvent for polymer synthesis, which can also be used for molecular imprinting, that can be used as an alternative to conventional and sometimes flammable or toxic polymerization solvents.

Place, publisher, year, edition, pages
Växjö: Linnaeus University Press, 2018. p. 68
Series
Linnaeus University Dissertations ; 329
Keywords
Liquid crystalline media, molecularly imprinted polymers, non-ionic deep eutectic solvents, quartz crystal microbalance
National Category
Organic Chemistry
Research subject
Chemistry, Organic Chemistry
Identifiers
urn:nbn:se:lnu:diva-78271 (URN)978-91-88761-96-5 (ISBN)978-91-88761-97-2 (ISBN)
Opponent
Supervisors
Available from: 2018-10-25 Created: 2018-10-11 Last updated: 2018-10-25Bibliographically approved
Suriyanarayanan, S., Nawaz, H., Ndizeye, N. & Nicholls, I. A. (2014). Hierarchical Thin Film Architectures for Enhanced Sensor Performance: Liquid Crystal-Mediated Electrochemical Synthesis of Nanostructured Imprinted Polymer Films for the Selective Recognition of Bupivacaine. Biosensors, 4(2), 90-110
Open this publication in new window or tab >>Hierarchical Thin Film Architectures for Enhanced Sensor Performance: Liquid Crystal-Mediated Electrochemical Synthesis of Nanostructured Imprinted Polymer Films for the Selective Recognition of Bupivacaine
2014 (English)In: Biosensors, ISSN 2079-6374, Vol. 4, no 2, p. 90-110Article in journal (Refereed) Published
Abstract [en]

Nanostructured bupivacaine-selective molecularly imprinted 3-aminophenylboronic acid-p-phenylenediamine co-polymer (MIP) films have been prepared on gold-coated quartz (Au/quartz) resonators by electrochemical synthesis under cyclic voltammetric conditions in a liquid crystalline (LC) medium (triton X-100/water). Films prepared in water and in the absence of template were used for control studies. Infrared spectroscopic studies demonstrated comparable chemical compositions for LC and control polymer films. SEM studies revealed that the topologies of the molecularly imprinted polymer films prepared in the LC medium (LC-MIP) exhibit discernible 40 nm thick nano-fiber structures, quite unlike the polymers prepared in the absence of the LC-phase. The sensitivity of the LC-MIP in a quartz crystal microbalance (QCM) sensor platform was 67.6 ± 4.9 Hz/mM under flow injection analysis (FIA) conditions, which was ≈250% higher than for the sensor prepared using the aqueous medium. Detection was possible at 100 nM (30 ng/mL), and discrimination of bupivacaine from closely related structural analogs was readily achieved as reflected in the corresponding stability constants of the MIP-analyte complexes. The facile fabrication and significant enhancement in sensor sensitivity together highlight the potential of this LC-based imprinting strategy for fabrication of polymeric materials with hierarchical architectures, in particular for use in surface-dependent application areas, e.g., biomaterials or sensing.

Keywords
bupivacaine, electropolymerization, liquid crystal, molecularly imprinted polymer, nanostructured polymer films, piezoelectric sensor, quartz crystal microbalance
National Category
Materials Chemistry
Research subject
Chemistry, Organic Chemistry
Identifiers
urn:nbn:se:lnu:diva-42605 (URN)10.3390/bios4020090 (DOI)2-s2.0-84902329632 (Scopus ID)
Funder
Swedish Research CouncilKnowledge Foundation
Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2018-11-02Bibliographically approved
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