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Levin I, Radulescu A, Liberman L, Cohen Y. Block Copolymer Adsorption on the Surface of Multi-Walled Carbon Nanotubes for Dispersion in N, N Dimethyl Formamide. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:838. [PMID: 36903716 PMCID: PMC10004759 DOI: 10.3390/nano13050838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/19/2023] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
This research aims to characterize the adsorption morphology of block copolymer dispersants of the styrene-block-4-vinylpyridine family (S4VP) on the surface of multi-walled carbon nanotubes (MWCNT) in a polar organic solvent, N,N-dimethyl formamide (DMF). Good, unagglomerated dispersion is important in several applications such as fabricating CNT nanocomposites in a polymer film for electronic or optical devices. Small-angle neutron scattering (SANS) measurements, using the contrast variation (CV) method, are used to evaluate the density and extension of the polymer chains adsorbed on the nanotube surface, which can yield insight into the means of successful dispersion. The results show that the block copolymers adsorb onto the MWCNT surface as a continuous coverage of low polymer concentration. Poly(styrene) (PS) blocks adsorb more tightly, forming a 20 Å layer containing about 6 wt.% PS, whereas poly(4-vinylpyridine) (P4VP) blocks emanate into the solvent, forming a thicker shell (totaling 110 Å in radius) but of very dilute (<1 wt.%) polymer concentration. This indicates strong chain extension. Increasing the PS molecular weight increases the thickness of the adsorbed layer but decreases the overall polymer concentration within it. These results are relevant for the ability of dispersed CNTs to form a strong interface with matrix polymers in composites, due to the extension of the 4VP chains allowing for entanglement with matrix chains. The sparse polymer coverage of the CNT surface may provide sufficient space to form CNT-CNT contacts in processed films and composites, which are important for electrical or thermal conductivity.
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Affiliation(s)
- Irena Levin
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Aurel Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-4) at Heinz Maier-Leibnitz Zentrum (MLZ), D-85747 Garching, Germany
| | - Lucy Liberman
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yachin Cohen
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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2
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Topcu G, Reinoso Arenas D, McNally T, Becer CR. Microphase separation assisted reduction in the percolation threshold of MWCNT/block polymer composites. SOFT MATTER 2023; 19:1109-1114. [PMID: 36648757 DOI: 10.1039/d2sm01277d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Block copolymers continue to attract a great deal of interest since they allow the formation of microphase-separated domains, useful for nanopatterning/templating. Herein, we present the drastic effect of microphase separation of a diblock copolymer on the electrical properties of polymer nanocomposites. Microphase-separated poly(styrene-b-2-ethylhexyl acrylate) (P(St-b-EHA)) block copolymers having different block lengths were synthesized and utilized as templates for multi-walled carbon nanotubes (MWCNTs). The percolation threshold of the films decreased from 0.46 to 0.19 vol% with decreasing styrene phase fraction. More importantly, we observed a non-linear and unique reduction in percolation threshold with transforming the phase into lamellar structures.
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Affiliation(s)
- Gokhan Topcu
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
| | - David Reinoso Arenas
- International Institute for Nanocomposites Manufacturing (IINM), WMG, University of Warwick, Coventry, CV4 7AL, UK
| | - Tony McNally
- International Institute for Nanocomposites Manufacturing (IINM), WMG, University of Warwick, Coventry, CV4 7AL, UK
| | - C Remzi Becer
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
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3
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Esmeraldo Paiva A, Baez Vasquez JF, Selkirk A, Prochukhan N, G L Medeiros Borsagli F, Morris M. Highly Ordered Porous Inorganic Structures via Block Copolymer Lithography: An Application of the Versatile and Selective Infiltration of the "Inverse" P2VP- b-PS System. ACS APPLIED MATERIALS & INTERFACES 2022; 14:35265-35275. [PMID: 35876355 DOI: 10.1021/acsami.2c10338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A facile and versatile strategy was developed to produce highly ordered porous metal oxide structures via block copolymer (BCP) lithography. Phase separation of poly(2-vinylpyridine)-b-polystyrene (P2VP-b-PS) was induced by solvent vapor annealing in a nonselective solvent environment to fabricate cylindrical arrays. In this work, we thoroughly analyzed the effects of the film thickness, solvent annealing time, and temperature on the ordering of a P2VP-majority system for the first time, resulting in "inverse" structures. Reflectometry, atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy were used to characterize the formation of the highly ordered BCP morphology and the subsequently produced metal oxide film. At 40 min solvent annealing time, hexagonally close packed structures were produced with cylinder diameters ∼40 nm. Subsequently, the BCP films were infiltrated with different metal cations. Metal ions (Cr, Fe, Ni, and Ga) selectively infiltrated the P2VP domain, while the PS did not retain any detectable amount of metal precursor. This gave rise to a metal oxide porous structure after a UV/ozone (UVO) treatment. The results showed that the metal oxide structures demonstrated high fidelity compared to the BCP template and cylindrical domains presented a similar size to the previous PS structure. Moreover, XPS analyses revealed the complete elimination of the BCP template and confirmed the presence of the metal oxides. These metal oxides were used as hard masks for pattern transfer via dry etching as a further application. Silicon nanopores were fabricated mimicking the BCP template and demonstrated a pore depth of ∼50 nm. Ultimately, this strategy can be applied to create different inorganic nanostructures for a diverse range of applications, for example, solar cells, diodes, and integrated circuits. Furthermore, by optimizing the etching parameters, deeper structures can be obtained via ICP/RIE processes, leading to many potential applications.
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Affiliation(s)
- Aislan Esmeraldo Paiva
- AMBER Research Centre/School of Chemistry, Trinity College Dublin, Dublin D02W085, Ireland
| | | | - Andrew Selkirk
- AMBER Research Centre/School of Chemistry, Trinity College Dublin, Dublin D02W085, Ireland
| | - Nadezda Prochukhan
- AMBER Research Centre/School of Chemistry, Trinity College Dublin, Dublin D02W085, Ireland
| | - Fernanda G L Medeiros Borsagli
- Institute of Engineering, Science and Technology, Universidade Federal dos Vales do Jequitinhonha e Mucuri/UFVJM, Av. 01, 4050, Janaúba, MG 39440-039, Brazil
| | - Michael Morris
- AMBER Research Centre/School of Chemistry, Trinity College Dublin, Dublin D02W085, Ireland
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Gao J, Li T, Song M, Zhao Y, Wang A. Effective dispersion of oxidized multi-walled carbon nanotubes using a water-soluble N, O-carboxymethyl chitosan via non-covalent interaction. RSC Adv 2022; 12:23754-23761. [PMID: 36090392 PMCID: PMC9394589 DOI: 10.1039/d2ra03592h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 08/16/2022] [Indexed: 11/26/2022] Open
Abstract
Dispersible multi-walled carbon nanotubes (MWCNTs) in water have been widely applied in the nanotechnology field. This study reports a water-soluble N,O-carboxymethyl chitosan(N,O-CMCS) assisted individual dispersion of oxidized multi-walled carbon nanotubes (oMWCNTs) as a dispersant. First, the dispersing agent N,O-CMCS was successfully synthesized using the nucleophilic substitution of deacetylated chitosan with chloroacetic acid in an alkaline solution. It was further confirmed using Fourier transform infrared spectroscopy (FTIR). Second, after the treatment with the concentrated hydrochloric acid, the prepared oMWCNTs were dispersed in an aqueous solution of N,O-CMCS under ultrasonic vibrations. Finally, the dispersed aqueous solution was subjected to centrifugation to collect the supernatant of individually dispersed N,O-CMCS/oMWCNTs. In addition, transmission electron microscopy (TEM) further confirmed that the purity of oMWCNTs was improved after the acidification progress. Besides, the stability of the dispersion solution was evidenced by digital photos of oMWCNTs dispersed by N,O-CMCS before and after. Moreover, the UV-vis spectrum (the characteristic peak of dispersed oMWCNTs downshifted 13 nm) showed that the supernatant was enriched by the individual oMWCNTs. In particular, the analytical results of FTIR (the –NH2 band of N,O-CMCS downshifted 7 cm−1), resonance Raman spectroscopy (the ID/IG ratio of dispersed oMWCNTs only increased 0.14), and XRD identified the formation of a non-convalent interaction between N,O-CMCS and oMWCNTs. These findings reveal the dispersing nature of N,O-CMCS towards oMWCNTs in water media. The stability of a dispersion solution was evidenced by images of oMWCNTs-dispersed by N,O-CMCS before (b) and after (a). UV-vis further showed that individual oMWCNTs were enriched via the non-covalent interaction between oMWCNTs and N,O-CMCS.![]()
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Affiliation(s)
- Jinling Gao
- College of Science, Heilongjiang Bayi Agricultural University, Daqing, 163319, China
| | - Tongtong Li
- College of Science, Heilongjiang Bayi Agricultural University, Daqing, 163319, China
| | - Mingzhe Song
- College of Science, Heilongjiang Bayi Agricultural University, Daqing, 163319, China
| | - Yuyao Zhao
- College of Science, Heilongjiang Bayi Agricultural University, Daqing, 163319, China
| | - Anxu Wang
- College of Science, Heilongjiang Bayi Agricultural University, Daqing, 163319, China
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Zhou Y, Firkowska-Boden I, Arras MML, Jandt KD. Polystyrene Homopolymer Enhances Dispersion of MWCNTs Stabilized in Solution by a PS- b-P2VP Copolymer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:391-399. [PMID: 33356302 DOI: 10.1021/acs.langmuir.0c03042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Block copolymers (BCPs) have previously been identified as powerful multiwalled carbon nanotube (MWCNT) dispersants in solution. However, relatively high costs and limited dispersibility hinder the use of BCPs in large-scale practical applications. Partial replacement of BCP with a low-cost homopolymer (HP) offers a promising approach to produce cost-effective MWNCT dispersions. The effect of HP/BCP blends on MWNCT dispersion degree and stability has yet to be elucidated. In this work, we tested the hypothesis that HP-induced BCP micelle size variation affects MWCNT dispersibility. Here, blends of the BCP poly(styrene)-block-poly(2-vinylpyridine) and the HP polystyrene (PS) were applied to examine BCP micelles' size dependence on the MWCNT dispersion degree. Light microscopy results showed that using HP/BCP blends, MWCNT dispersion was enhanced by up to 263% compared to pure BCP at a constant weight ratio of BCP to MWCNTs. Based on the correlation of increased MWCNT dispersion degree with increased BCP micelle size, as revealed by dynamic light scattering, an MWCNT dispersion mechanism is proposed. The mechanism includes a rationale for the unexpected finding that HP PS swells the BCP micelle's PS corona in a good solvent for PS. Using HP to increase MWCNT dispersion is a promising approach with possible applications in the production of high-performance composite materials. This holds especially for formulations of practical relevance where often (BCP) dispersants are only one of many components in the material.
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Affiliation(s)
- Yingying Zhou
- Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
- School of Materials Engineering, Xi'an Aeronautical University, Xi'an 710077, P.R. China
| | - Izabela Firkowska-Boden
- Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
| | - Matthias M L Arras
- Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
| | - Klaus D Jandt
- Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
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Dockendorff J, Mourran A, Gumerov RA, Potemkin II, Möller M, Gauthier M. Metal Coordination Induces Phase Segregation in Amphipolar Arborescent Copolymers with a Core–Shell–Corona Architecture. Macromolecules 2020; 53:8108-8122. [PMID: 35516458 PMCID: PMC9062874 DOI: 10.1021/acs.macromol.0c00778] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/07/2020] [Indexed: 01/08/2023]
Abstract
![]()
Arborescent
copolymers with a core–shell–corona (CSC)
architecture were synthesized and the topology of the molecules was
challenged (constrained) through intramolecular interactions, resulting
in phase separation breaking the symmetry of radial density. The inner
poly(2-vinylpyridine) shell of these arborescent polystyrene-g-[poly(2-vinylpyridine)-b-polystyrene]
molecules can self-assemble by binding metallic salts and acids in
apolar and intermediate-polarity solvents. Upon loading with HAuCl4, the characteristics of the polymer templates govern the
“loading sites” of the metal within the molecules. Unique
morphologies were observed for the metal-loaded G0–G4 arborescent
copolymers investigated, namely, spherical, toroidal, raspberry-like,
spherical nanocage, and a new worm-in-sphere morphology. The reason
for the emergence of such morphologies is the interplay among intramolecular
interactions of unlike polymer segments, solvent selectivity, the
entropic elasticity of the arborescent substrate, and phase segregation
induced by coordination with the charged metallic species. Meanwhile,
the stability of the arborescent molecules against aggregation provides
intramolecular phase segregation with imposed “confined”
geometry and thus leads to nonconventional morphologies. Furthermore,
the size of the arborescent molecules is much smaller than that of
other known particles (droplets) serving as confined geometries. Computer
simulations were used to model the mesostructure of the arborescent
copolymers, to demonstrate the influence of solvent selectivity, together
with HAuCl4 loading, on the evolution of the morphology
of the macromolecules.
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Affiliation(s)
- Jason Dockendorff
- Department of Chemistry, Institute for Polymer Research and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Ahmed Mourran
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, D-52056 Aachen, Germany
| | - Rustam A. Gumerov
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, D-52056 Aachen, Germany
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
| | - Igor I. Potemkin
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, D-52056 Aachen, Germany
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
- South Ural State University (National Research University), Chelyabinsk 454080, Russian Federation
| | - Martin Möller
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, D-52056 Aachen, Germany
| | - Mario Gauthier
- Department of Chemistry, Institute for Polymer Research and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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