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Wong J, Toader V, Reven L. Lyotropic Nematic Phases of Isotropic Nanoparticles via Semiflexible Polymer Ligands. Macromol Rapid Commun 2023; 44:e2200951. [PMID: 36700516 DOI: 10.1002/marc.202200951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Indexed: 01/27/2023]
Abstract
Lyotropic liquid crystalline (LC) nanomaterials are normally achieved through particle shape anisotropy. Herein, it is shown that lyotropic nematic rather than cubic phases are produced from spherical nanoparticles (NPs) with semi-flexible polymer ligands. ZrO2 nanocrystals (4 nm dia.) are coated with a dense shell of poly(hexyl isocyanate) (PHIC), a helical rod-like polymer that forms lyotropic LC phases in a range of organic solvents. Solvent casted NPs with PHIC ligands above the persistence length form linear assemblies, separated by a characteristic distance related to the chain length while NPs with shorter, rigid rod PHIC ligands pack hexagonally. Concentrated NP-PHIC dispersions present nematic textures similar to the free PHIC nematic solutions but at lower critical concentrations, widening the isotropic-nematic biphasic region. 2 H NMR spectra of the NPs dispersed in a deuterated solvent display quadrupolar splittings that increase with NP concentration, showing that the PHIC ligands are magnetically aligned. The high degree of orientation order is evidence that splaying of the ligand shell transforms the spherical NPs to rod-like shapes that assemble to produce nematic lyotropic LC phases and linear NP arrays. This approach to creating anisotropic assemblies can be extended to other types of spherical NPs and semiflexible polymers.
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Affiliation(s)
- Jessie Wong
- Department of Chemistry and Centre québécois sur les matériaux fonctionnels/Quebec Centre for Advanced Materials (CQMF/QCAM), McGill University, 801 Sherbrooke St. W., Montreal, Quebec, H3A 0B8, Canada
| | - Violeta Toader
- Department of Chemistry and Centre québécois sur les matériaux fonctionnels/Quebec Centre for Advanced Materials (CQMF/QCAM), McGill University, 801 Sherbrooke St. W., Montreal, Quebec, H3A 0B8, Canada
| | - Linda Reven
- Department of Chemistry and Centre québécois sur les matériaux fonctionnels/Quebec Centre for Advanced Materials (CQMF/QCAM), McGill University, 801 Sherbrooke St. W., Montreal, Quebec, H3A 0B8, Canada
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Abstract
Spontaneous phase separation in binary mixed ligand shells is a proposed strategy to create patchy nanoparticles. The surface anisotropy, providing directionality along with interfacial properties emerging from both ligands, is highly desirable for targeted drug delivery, catalysis, and other applications. However, characterization of phase separation on the nanoscale remains quite challenging. Here we have adapted solid-state 1H spin diffusion NMR experiments designed to detect and quantify spatial heterogeneity in polymeric materials to nanoparticles (NPs) functionalized with mixed short ligands. Janus NPs and physical mixtures of homoligand 3.5 nm diameter ZrO2 NPs, with aromatic (phenylphosphonic acid, PPA) and aliphatic (oleic acid, OA) ligands, were used to calibrate the 1H spin diffusion experiments. The Janus NPs, prepared by a facile wax/water Pickering emulsion method, and mixed ligand NPs, produced by ligand exchange, both with 1:1 PPA:OA ligand compositions, display strikingly different solvent and particle-particle interactions. 1H spin diffusion NMR experiments are most consistent with a lamellar surface pattern for the mixed ligand ZrO2 NPs. Solid-state 1H spin diffusion NMR is shown to be a valuable additional characterization tool for mixed ligand NPs, as it not only detects the presence of nanoscale phase separation but also allows measurement of the domain sizes and geometries of the surface phase separation.
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Affiliation(s)
- Brenda Guzman-Juarez
- Centre Québécois sur les Matériaux Fonctionnels/Quebec Centre for Advanced Materials (CQMF/QCAM), Department of Chemistry, McGill University, 801 Sherbrooke Street W., MontrealQuebec, CanadaH3A 0B8
| | - Ahmed Bahaeldin Abdelaal
- Centre Québécois sur les Matériaux Fonctionnels/Quebec Centre for Advanced Materials (CQMF/QCAM), Department of Chemistry, McGill University, 801 Sherbrooke Street W., MontrealQuebec, CanadaH3A 0B8
| | - Linda Reven
- Centre Québécois sur les Matériaux Fonctionnels/Quebec Centre for Advanced Materials (CQMF/QCAM), Department of Chemistry, McGill University, 801 Sherbrooke Street W., MontrealQuebec, CanadaH3A 0B8
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Romero Esquivel G, Toader V, Reven L, Kambhampati P. Ligand-flexible synthesis of strongly confined perovskite nanocrystals: a microwave synthetic approach. Nanoscale 2022; 14:15789-15798. [PMID: 36250330 DOI: 10.1039/d2nr04597d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Perovskite nanocrystals (PNCs) and their strongly confined versions have traditionally been synthesized via hot injection methods. However, there is a pressing need for a new synthesis method that offers more flexible surface chemistry, improved optical properties, and greater sample stability. Here we explore and exploit the recently introduced microwave (MW) synthesis method, focusing on temperature and coating ligands, including a polymer ligand for which the hot injection method is unsuitable. The optimized microwave synthetic protocols produce PNCs with better exciton definition, lower polydispersity, and stronger ligand attachment than their hot injection counterparts. A variety of characterization techniques were employed to compare the properties of PNCs produced by the hot injection versus microwave methods. Insight into the molecular basis for the improved PNC properties was provided by FTIR and several NMR experiments that revealed the nature of the attachment of different ligands and their interactions with the PNCs. The overall results demonstrate that MW synthesis is a promising alternative to the HI method, particularly if smaller PNCs with strong quantum confinement are desired.
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Affiliation(s)
| | - Violeta Toader
- Department of Chemistry, McGill University, Montreal, Canada.
| | - Linda Reven
- Department of Chemistry, McGill University, Montreal, Canada.
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Zhang M, Lindner-D’Addario M, Roohnikan M, Toader V, Lennox RB, Reven L. Polymer Functionalized Nanoparticles in Blue Phase LC: Effect of Particle Shape. Nanomaterials (Basel) 2021; 12:nano12010091. [PMID: 35010041 PMCID: PMC8746361 DOI: 10.3390/nano12010091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/10/2021] [Accepted: 12/19/2021] [Indexed: 02/02/2023]
Abstract
Ethylene oxide oligomers and polymers, free and tethered to gold nanoparticles, were dispersed in blue phase liquid crystals (BPLC). Gold nanospheres (AuNPs) and nanorods (AuNRs) were functionalized with thiolated ethylene oxide ligands with molecular weights ranging from 200 to 5000 g/mol. The BPLC mixture (ΔTBP ~6 °C) was based on the mesogenic acid heterodimers, n-hexylbenzoic acid (6BA) and n-trans-butylcyclohexylcarboxylic acid (4-BCHA) with the chiral dopant (R)-2-octyl 4-[4-(hexyloxy)benzoyloxy]benzoate. The lowest molecular weight oligomer lowered and widened the BP range but adding AuNPs functionalized with the same ligand had little effect. Higher concentrations or molecular weights of the ligands, free or tethered to the AuNPs, completely destabilized the BP. Mini-AuNRs functionalized with the same ligands lowered and widened the BP temperature range with longer mini-AuNRs having a larger effect. In contrast to the AuNPs, the mini-AuNRs with the higher molecular weight ligands widened rather than destabilized the BP, though the lowest MW ligand yielded the largest BP range, (ΔTBP > 13 °C). The different effects on the BP may be due to the AuNPs accumulating at singular defect sites whereas the mini-AuNRs, with diameters smaller than that of the disclination lines, can more efficiently fill in the BP defects.
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Guzman-Juarez B, Abdelaal A, Kim K, Toader V, Reven L. Fabrication of Amphiphilic Nanoparticles via Mixed Homopolymer Brushes and NMR Characterization of Surface Phase Separation. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01959] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Brenda Guzman-Juarez
- Quebec Center for Advanced Materials (QCAM), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
| | - Ahmed Abdelaal
- Quebec Center for Advanced Materials (QCAM), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
| | - Kuenhee Kim
- Quebec Center for Advanced Materials (QCAM), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
| | - Violeta Toader
- Quebec Center for Advanced Materials (QCAM), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
| | - Linda Reven
- Quebec Center for Advanced Materials (QCAM), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
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Allie S, Hegoburu I, Shin MJ, Jung JY, Toader V, Rey A, Soule ER, Reven L. Polymer functionalized nanoparticles in liquid crystals: combining PDLCs with LC nanocomposites. Soft Matter 2018; 14:8580-8589. [PMID: 30318545 DOI: 10.1039/c8sm01192c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Liquid crystal (LC)-polymer blends are important stimuli responsive materials already employed in a wide range of applications whereas nanoparticle (NP)-LC blends are an emerging class of nanocomposites. Polymer ligands offer the advantages of synthetic simplicity along with chemical and molecular weight tunability. Here we compare the phase behavior of 5CB blended with poly(ethylene oxide) (PEO) and with gold NPs functionalized with thiolated PEO (AuNP-PEO) as a function of PEO concentration by DSC, POM and 13C NMR spectroscopy. Both PEO and the AuNP-PEO form uniform dispersions in isotropic 5CB and phase separate below the I-N phase transition temperature. Above the PEO crystallization temperature, the PEO/5CB blends show the expected biphasic state of PEO rich-isotropic liquid co-existing with PEO-poor nematic droplets. At PEO concentrations above 10 wt%, nematic 5CB nucleates with PEO crystallization. Both PEO and AuNP-PEO induce homeotropic alignment of the 5CB matrix immediately below TNI. The AuNP-PEO/5CB blends form thermally reversible cellular networks similar to AuNPs functionalized with low molecular weight mesogenic ligands. A thermodynamic model to account for the observed phase behavior is presented.
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Affiliation(s)
- Safiya Allie
- Quebec Centre for Advanced Materials, Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal QC H3A 0B8, Canada.
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Abstract
Nanoparticle-liquid crystal (NP-LC) composites based on hydrogen bonding were explored using a model system. The ligand shells of 3 nm diameter zirconium dioxide nanoparticles (ZrO2 NPs) were varied to control their interaction with 4-n-hexylbenzoic acid (6BA). The miscibility and effect of the NPs on the nematic order as a function of particle concentration was characterized by polarized optical microscopy (POM), fluorescence microscopy and (2)H NMR spectroscopy. Nonfunctionalized ZrO2 NPs have the lowest miscibility and strongest effect on the LC matrix due to irreversible binding of 6BA to the NPs via a strong zirconium carboxylate bond. The ZrO2 NPs were functionalized with 6-phosphonohexanoic acid (6PHA) or 4-(6-phosphonohexyloxy)benzoic acid (6BPHA) which selectively bind to the ZrO2 NP surface via the phosphonic acid groups. The miscibility was increased by controlling the concentration of the pendant CO2H groups by adding hexylphosphonic acid (HPA) to act as a spacer group. Fluorescence microscopy of lanthanide doped ZrO2 NPs showed no aggregates in the nematic phase below the NP concentration where aggregates are observed in the isotropic phase. The functionalized NPs preferably concentrate into LC defects and any remaining isotropic liquid but are still present throughout the nematic liquid at a lower concentration.
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Affiliation(s)
- Mahdi Roohnikan
- Department of Chemistry, Centre for Self-Assembled Chemical Structures (CSACS) , 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
- Department of Chemical Engineering, McGill University , Montreal, Quebec H3A 0C5, Canada
| | - Violeta Toader
- Department of Chemistry, Centre for Self-Assembled Chemical Structures (CSACS) , 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Alejandro Rey
- Department of Chemical Engineering, McGill University , Montreal, Quebec H3A 0C5, Canada
| | - Linda Reven
- Department of Chemistry, Centre for Self-Assembled Chemical Structures (CSACS) , 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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Gharbi MA, Manet S, Lhermitte J, Brown S, Milette J, Toader V, Sutton M, Reven L. Reversible Nanoparticle Cubic Lattices in Blue Phase Liquid Crystals. ACS Nano 2016; 10:3410-5. [PMID: 26900753 DOI: 10.1021/acsnano.5b07379] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Blue phases (BPs), a distinct class of liquid crystals (LCs) with 3D periodic ordering of double twist cylinders involving orthogonal helical director twists, have been theoretically studied as potential templates for tunable colloidal crystals. Here, we report the spontaneous formation of thermally reversible, cubic crystal nanoparticle (NP) assemblies in BPs. Gold NPs, functionalized to be highly miscible in cyanobiphenyl-based LCs, were dispersed in BP mixtures and characterized by polarized optical microscopy and synchrotron small-angle X-ray scattering (SAXS). The NPs assemble by selectively migrating to periodic strong trapping sites in the BP disclination lines. The NP lattice, remarkably robust given the small particle size (4.5 nm diameter), is commensurate with that of the BP matrix. At the BP I to BP II phase transition, the NP lattice reversibly switches between two different cubic structures. The simultaneous presence of two different symmetries in a single material presents an interesting opportunity to develop novel dynamic optical materials.
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Affiliation(s)
- Mohamed Amine Gharbi
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada
- Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada
| | - Sabine Manet
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada
- Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada
| | - Julien Lhermitte
- Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada
| | - Sarah Brown
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada
- Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada
| | - Jonathan Milette
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada
| | - Violeta Toader
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada
| | - Mark Sutton
- Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada
| | - Linda Reven
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada
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Leonardi A, Puig J, Antonacci J, Arenas G, Zucchi I, Hoppe C, Reven L, Zhu L, Toader V, Williams R. Remote activation by green-light irradiation of shape memory epoxies containing gold nanoparticles. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.08.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Gurevich S, Soule E, Rey A, Reven L, Provatas N. Self-assembly via branching morphologies in nematic liquid-crystal nanocomposites. Phys Rev E Stat Nonlin Soft Matter Phys 2014; 90:020501. [PMID: 25215674 DOI: 10.1103/physreve.90.020501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Indexed: 06/03/2023]
Abstract
We demonstrate that the morphological diversity in liquid-crystal hybrid systems is much richer than previously anticipated. More importantly, we reveal the existence of a dual mechanism for self-assembly of nanoparticles via morphological instabilities at phase boundaries. Using numerical simulations, we study the growth of isolated nematic droplets in an isotropic liquid crystal (LC) doped with nanoparticles (NPs) and provide insight into the nature of microstructure evolution in LC hybrids. Our work expands the numerically accessible time and length scales in these systems, capturing morphologies which develop under the competition of nonequilibrium elastic interactions, diffusive instabilities mediated by NP transport, and the anisotropy of the nematic field. By mapping nematic morphologies, we also propose a methodology for estimating various important LC material parameters that are difficult to obtain experimentally.
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Affiliation(s)
- Sebastian Gurevich
- Department of Physics, Centre for the Physics of Materials, McGill University, Montreal, Quebec, Canada and Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada
| | - Ezequiel Soule
- Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), Mar del Plata, Argentina
| | - Alejandro Rey
- Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada
| | - Linda Reven
- Chemistry Department, McGill University, Montreal, Quebec, Canada
| | - Nikolas Provatas
- Department of Physics, Centre for the Physics of Materials, McGill University, Montreal, Quebec, Canada
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Affiliation(s)
- Blythe Fortier-McGill
- Centre
for Self-Assembled
Chemical Structures (CSACS-CRMAA), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
| | - Violeta Toader
- Centre
for Self-Assembled
Chemical Structures (CSACS-CRMAA), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
| | - Linda Reven
- Centre
for Self-Assembled
Chemical Structures (CSACS-CRMAA), Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
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Hu H, Reven L, Rey A. First-Principles Density Functional Theory (DFT) Study of Gold Nanorod and Its Interaction with Alkanethiol Ligands. J Phys Chem B 2013; 117:12625-31. [PMID: 24083822 DOI: 10.1021/jp4028589] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Hang Hu
- Department
of Chemical Engineering, McGill University, 845 Sherbrook Street West, Montreal, Quebec, Canada, H3A 0G4
| | - Linda Reven
- Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec Canada, H3A 2K6
| | - Alejandro Rey
- Department
of Chemical Engineering, McGill University, 845 Sherbrook Street West, Montreal, Quebec, Canada, H3A 0G4
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Hu H, Reven L, Rey AD. Ab initioDFT study of 6-mercapto-hexane SAMs: effect of Au surface defects on the monolayer assembly. Molecular Simulation 2013. [DOI: 10.1080/08927022.2012.720018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Milette J, Toader V, Soulé ER, Lennox RB, Rey AD, Reven L. A molecular and thermodynamic view of the assembly of gold nanoparticles in nematic liquid crystal. Langmuir 2013; 29:1258-1263. [PMID: 23294352 DOI: 10.1021/la304189n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The molecular interactions driving the assembly of gold nanoparticles (AuNPs) in a nematic liquid crystal (LC) are directly detected by nuclear magnetic resonance (NMR) spectroscopy and thermodynamically analyzed. The orientational orders of the selectively deuterated LC matrix and AuNP ligands, each separately followed by variable temperature (2)H NMR as a function of particle concentration, were observed to be strongly correlated. The mechanism of the reversible formation of long-range, quasi-periodic nanoparticle structures is attributed to the coupling of the AuNP ligands to the LC matrix, inducing an isotropic-nematic biphasic state. Experimentally validated thermodynamic modeling shows that, in contrast to colloidal nematics that are dominated by elastic forces, nematic dispersions of nanoparticles self-organize through a subtle balance of entropic forces and excluded volume, interface-mediated mesogen and nanoparticle molecular interactions, and couplings between conserved and nonconserved order parameters. Fine-tuning of these interactions through ligand and mesogen chemistry, together with mesoscale modeling, provides a route for materials innovations by merging structured fluid physics and nanoscience.
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Affiliation(s)
- Jonathan Milette
- Centre for Self-assembled Chemical Structures, Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, QC H4A 3B7, Canada
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15
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Affiliation(s)
- Blythe Fortier-McGill
- Centre for Self-Assembled Chemical Structures (CSACS-CRMAA),
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8 Canada
| | - Violeta Toader
- Centre for Self-Assembled Chemical Structures (CSACS-CRMAA),
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8 Canada
| | - Linda Reven
- Centre for Self-Assembled Chemical Structures (CSACS-CRMAA),
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8 Canada
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Soulé ER, Lavigne C, Reven L, Rey AD. Multiple interfaces in diffusional phase transitions in binary mesogen-nonmesogen mixtures undergoing metastable phase separations. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 86:011605. [PMID: 23005428 DOI: 10.1103/physreve.86.011605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Indexed: 06/01/2023]
Abstract
Theory and simulations of simultaneous chemical demixing and phase ordering are performed for a mixed order parameter system with an isotropic-isotropic (I-I) phase separation that is metastable with respect to an isotropic-nematic (I-N) phase-ordering transition. Under certain conditions, the disordered phase transforms into an ordered phase via the motion of a double front containing a metastable phase produced by I-I demixing, a thermodynamically driven mechanism not previously reported. Different kinetic regimes are found depending on the location of the initial conditions in the thermodynamic phase diagram and the ratio between diffusional and nematic phase-ordering mobilities. For a diffusional process, depending if the temperature is above or below the critical codissolution point, an inflection point or a phase separation takes place in the depletion layer. This phase separation leads to the formation of a second interface where the separation of the two metastable isotropic phases grows monotonically with time. The observed deviations from the typical Fickian concentration profiles are associated with strong positive deviations of the mixture from ideality due to couplings between concentration and nematic ordering. Although systems of interest include liquid-crystalline nanocomposites, this mechanism may apply to any mixture that can undergo an order-disorder transition and demix.
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Affiliation(s)
- Ezequiel R Soulé
- Institute of Materials Science and Technology, INTEMA, University of Mar del Plata and National Research Council, CONICET, JB Justo 4302, 7600 Mar del Plata, Argentina
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Relaix S, Leheny RL, Reven L, Sutton M. Memory effect in composites of liquid crystal and silica aerosil. Phys Rev E Stat Nonlin Soft Matter Phys 2011; 84:061705. [PMID: 22304107 DOI: 10.1103/physreve.84.061705] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Indexed: 05/31/2023]
Abstract
Aerosil silica nanoparticles dispersed in a liquid crystal (LC) possess the interesting property of keeping memory of an electric- or magnetic-field-induced orientation. Two types of memory have been identified: thermally erasable memory arising from the pinning of defect lines versus a "permanent" memory where the orientation persists even after thermal cycling the samples up to the isotropic phase. To address the source of the latter type of memory, solid-state nuclear magnetic resonance spectroscopy and conventional x-ray diffraction (XRD) were first combined to characterize the LC orientational order as a function of multiple in-field temperature cycles. Microbeam XRD was then performed on aligned gels of different concentrations to gain knowledge of the structural properties at the origin of the memory effect. No detectable anisotropy of the gel or significant breaking of silica strands with heating ruled out the formation of an anisotropic silica network as the source of the permanent memory as previously proposed. Instead, support for a role of the surface memory effect, well known for planar substrates, in stabilizing the permanent memory was deduced from "training" of the composites, that is, optimizing the orientational order through the thermal in-field cycling. The ability to train the composites is inversely proportional to the strength of the random-field disorder. The portion of thermally erasable memory also decreases as the silica density increases. We propose that the permanent memory originates from the surface memory effect operating at points of intersection in the silica network. These areas, where the LC is strongly confined with conflicted surface interactions, are trained to achieve an optimized orientation and subsequently act as sites from which the LC orientational order regrows after zero-field thermal cycling up to the isotropic phase.
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Affiliation(s)
- Sabrina Relaix
- Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8
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Phillips PM, Mei N, Soulé ER, Reven L, Rey AD. Textures in polygonal arrangements of square nanoparticles in nematic liquid crystal matrices. Langmuir 2011; 27:13335-13341. [PMID: 21942338 DOI: 10.1021/la203226g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A systematic analysis of defect textures in faceted nanoparticles with polygonal configurations embedded in a nematic matrix is performed using the Landau-de Gennes model, homeotropic strong anchoring in a square domain with uniform alignment in the outer boundaries. Defect and textures are analyzed as functions of temperature T, polygon size R, and polygon number N. For nematic nanocomposites, the texture satisfies a defect charge balance equation between bulk and surface (particle corner) charges. Upon decreasing the temperature, the central bulk defects split and together with other -1/2 bulk defects are absorbed by the nanoparticle's corners. Increasing the lattice size decreases confinement and eliminates bulk defects. Increasing the polygon number increases the central defect charge at high temperature and the number of surface defects at lower temperatures. The excess energy per particle is lower in even than in odd polygons, and it is minimized for a square particle arrangement. These discrete modeling results show for first time that, even under strong anchoring, defects are attached to particles as corner defects, leaving behind a low energy homogeneous orientation field that favors nanoparticle ordering in nematic matrices. These new insights are consistent with recent thermodynamic approaches to nematic nanocomposites that predict the existence of novel nematic/crystal phases and can be used to design nanocomposites with orientational and positional order.
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Affiliation(s)
- Paul M Phillips
- Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A2B2, Canada
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Affiliation(s)
- Blythe Fortier-McGill
- Center for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, Quebec, Canada H3A 2K6
| | - Violeta Toader
- Center for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, Quebec, Canada H3A 2K6
| | - Linda Reven
- Center for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, Quebec, Canada H3A 2K6
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Milette J, Toader V, Reven L, Lennox RB. Tuning the miscibility of gold nanoparticles dispersed in liquid crystals via the thiol-for-DMAP reaction. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm10553a] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Affiliation(s)
- Blythe Fortier-McGill
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, 801 Sherbrook St. West, McGill University, Montreal, Quebec H3H 2K6, Canada
| | - Linda Reven
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, 801 Sherbrook St. West, McGill University, Montreal, Quebec H3H 2K6, Canada
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O'Donnell A, Yach K, Reven L. Particle-particle interactions and chain dynamics of fluorocarbon and hydrocarbon functionalized ZrO2 nanoparticles. Langmuir 2008; 24:2465-2471. [PMID: 18269295 DOI: 10.1021/la702503m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The chain conformation and dynamics of hydrocarbon and perfluorocarbon fatty acids adsorbed on 4 nm ZrO2 particles were characterized by solid-state 13C chemical shift and 19F NMR relaxation measurements, respectively, and compared to those from previous studies on lower surface area fumed metal oxide powders. The interdigitation of chains between neighboring particles, which increases with chain length, can be detected from the splitting of the 13C NMR and 19F NMR signals of the CH3 and CF3 groups, respectively. Similar to the case of alkanethiol self-assembled monolayers (SAMs) on gold nanoparticles, this interdigitation allows for efficient chain packing despite the high surface curvature. The hydrocarbon chains on the ZrO2 nanoparticles are more ordered, and the reversible chain length dependent order-disorder transition temperatures are elevated relative to those of the same fatty acids adsorbed on fumed ZrO2 powder. Likewise, the 19F spin lattice relaxation times of the fluorocarbon chains approach those of the bulk acids with increasing chain length and interdigitation, indicating densely packed chains.
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Affiliation(s)
- Andrew O'Donnell
- Centre for Self-Assembled Chemical Structures (CSACS), Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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Dorris A, Rucareanu S, Reven L, Barrett CJ, Lennox RB. Preparation and characterization of polyelectrolyte-coated gold nanoparticles. Langmuir 2008; 24:2532-2538. [PMID: 18229959 DOI: 10.1021/la703003m] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Gold nanoparticles of 5 nm diameter, stabilized by 4-(dimethylamino)pyridine (DMAP), were coated with poly(sodium 4-styrene sulfonate) (PSS) via electrostatic self-assembly. The suspension stability, monitored by the gold surface plasmon band (SPB), was studied by varying the pH, the PSS chain length, and PSS concentration. Enhanced stability is obtained at pH 10 (above the pKa of DMAP) when the polymer chain length matches or exceeds the particle circumference. Solid state 13C NMR was used to determine the presence of DMAP and polymers after subsequent deposition of weak and strong polycations: poly(allylamine hydrochloride) (PAH) and poly(diallyldimethylammonium chloride) (PDADMAC). At pH 10, DMAP remains associated with the nanoparticle after the first PSS layer has been formed. When PAH or PDADMAC are subsequently added at pH 4.5, DMAP is expelled, the suspensions remain stable, and zeta potential values indicate complete charge reversal. In the case of PDADMAC, however, the first layer of PSS is not fully retained. When PDADMAC is added at pH 10, DMAP and the first PSS layer are retained but lower zeta potentials and a higher SPB shift indicate a degraded stability. For PAH addition at pH 9.5, both DMAP and PSS are expelled and the suspension becomes unstable. These differences in stability of the multilayer components and the nanoparticle suspension are rationalized in terms of chain flexibility, polymer charge density, and the ability of the polymer functional groups to directly interact with the gold surface.
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Affiliation(s)
- Annie Dorris
- Centre for Self-Assembled Chemical Structures (CSACS), Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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24
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Affiliation(s)
- Jonathan Milette
- Centre for Self-Assembled Chemical Structures (CSACS), Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Québec, Canada H3A 2K6, and Department of Chemistry, Dawson College, 3040 Sherbrooke Street West, Westmount, Québec, Canada H3Z 1A4
| | - C. T. Yim
- Centre for Self-Assembled Chemical Structures (CSACS), Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Québec, Canada H3A 2K6, and Department of Chemistry, Dawson College, 3040 Sherbrooke Street West, Westmount, Québec, Canada H3Z 1A4
| | - Linda Reven
- Centre for Self-Assembled Chemical Structures (CSACS), Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Québec, Canada H3A 2K6, and Department of Chemistry, Dawson College, 3040 Sherbrooke Street West, Westmount, Québec, Canada H3Z 1A4
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Abstract
Gold nanoparticles capped with 11-mercaptoundecanylphosphonic acid (MUP) and sodium 10-mercaptodecanesulfonic acid (MDS) were characterized by a range of techniques which included solid-state 31P and 13C NMR spectroscopies. Despite similar core sizes and alkyl chain lengths, the conformational and dynamic properties of the capping ligands are very different for the two types of nanoparticles. Whereas MDS produces disordered monolayers on planar gold surfaces, the MDS-capped nanoparticles show a high degree of chain order with the onset of reversible chain disordering occurring just above room temperature. The alkyl chains of MUP adsorbed on the gold nanoparticles are more ordered and motionally restricted than the unbound solid surfactant due to strong intramonolayer and interparticle hydrogen bonds. This conformational order is thermally stable, and disordering only occurs upon decomposition and desorption of MUP from the gold core. Solid-state 31P NMR has been demonstrated to be a sensitive probe of the interactions of the PO3H2 terminal groups.
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Affiliation(s)
- Petr Fiurasek
- Centre for Self-Assembled Chemical Structures (CSACS), Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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Abstract
The bonding and dynamic properties of perfluoroalkanoic acid self-assembled monolayers (SAMs) on zirconia and titania powders were characterized by Fourier transform infrared and solid-state 19F magic-angle spinning NMR spectroscopy. The perfluoro fatty acids investigated included C(n)F(2n+1)CO2H, n = 7, 13, 15 and 17. The acids bind to both metal oxides via ionic carboxylate bonds, but complete monolayers are only formed on the zirconia. The shift of the CF3 group from -83 ppm in the bulk state to -85 ppm for the adsorbed monolayers is assigned to CF3 groups located at the air/monolayer interface. With the exception of the perfluorooctanoic acid, 19F spin lattice relaxation measurements indicate that the fluorocarbon chains of the adsorbed acids, even in the case of densely packed monolayers, are significantly more mobile than those in the bulk state. The motions associated with the enhanced mobility of the adsorbed acids are proposed to involve reorientations along the long chain axes. No evidence for chain melting in the fluorocarbon SAMs is found for temperatures well above the melting temperature of the bulk acids.
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Affiliation(s)
- Shane Pawsey
- Department of Chemistry, 801 Sherbrooke Street West, McGill University, Montreal Quebec, Canada H3A2K6
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Affiliation(s)
- Michael McAlduff
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - Linda Reven
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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Affiliation(s)
- Rashida N. Smith
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal Quebec, H3A 2K6, Canada, and Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany
| | - Mark McCormick
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal Quebec, H3A 2K6, Canada, and Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany
| | - Christopher J. Barrett
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal Quebec, H3A 2K6, Canada, and Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany
| | - Linda Reven
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal Quebec, H3A 2K6, Canada, and Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany
| | - Hans W. Spiess
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal Quebec, H3A 2K6, Canada, and Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany
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Yim CT, O'Donnell A, Yach K, Morin FG, Reven L. Deuterium NMR Study of the Dynamics of Self-Assembled Hexadecanoate Monolayers on Zirconium Oxide. J Phys Chem B 2003. [DOI: 10.1021/jp0347623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. T. Yim
- Department of Chemistry, Dawson College, 3040 Sherbrooke Street West, Westmount, Québec, Canada H3Z 1A4
| | - A. O'Donnell
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - K. Yach
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - F. G. Morin
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - L. Reven
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
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McCormick M, Smith RN, Graf R, Barrett CJ, Reven L, Spiess HW. NMR Studies of the Effect of Adsorbed Water on Polyelectrolyte Multilayer Films in the Solid State. Macromolecules 2003. [DOI: 10.1021/ma034147x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. McCormick
- Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany, and Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
| | - R. N. Smith
- Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany, and Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
| | - R. Graf
- Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany, and Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
| | - C. J. Barrett
- Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany, and Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
| | - L. Reven
- Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany, and Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
| | - H. W. Spiess
- Max Planck Institute for Polymer Research, Postfach 3148, 55118 Mainz, Germany, and Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
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Pawsey S, McCormick M, De Paul S, Graf R, Lee YS, Reven L, Spiess HW. 1H fast MAS NMR studies of hydrogen-bonding interactions in self-assembled monolayers. J Am Chem Soc 2003; 125:4174-84. [PMID: 12670240 DOI: 10.1021/ja029008u] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structures formed by the adsorption of carboxyalkylphosphonic acids on metal oxides were investigated by (1)H fast magic angle spinning (MAS), heteronuclear correlation (HETCOR), and (1)H double-quantum (DQ) MAS solid-state NMR experiments. The diacids HO(2)C(CH(2))(n)PO(3)H(2) (n = 2, 3, 11, and 15) were adsorbed on TiO(2) and two types of ZrO(2) powders having average particle sizes of 20, 30, and 5 nm, respectively. Carboxyalkylphosphonic acids bind selectively via the phosphonate group, forming monolayers with pendant carboxylic acid groups. Whereas dipolar coupled P-OH protons are detected on TiO(2), there are only isolated residual P-OH groups on ZrO(2), reflecting the relative binding strengths of phosphonic acids on these two substrates. From a comparative (1)H MAS NMR study with an analogous monolayer system, HO(2)C(CH(2))(7)SH coated gold nanoparticles, the hydrogen-bonding network at the monolayer/air interface is found to be quite disordered, at least for SAMs deposited on nonplanar substrates. Whereas only hydrogen-bonded homodimers occur in the bulk diacids, hydrogen bonding between the carboxylic and phosphonic acid groups is present in multilayers of the diacids on the ZrO(2) nanopowder.
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Affiliation(s)
- Shane Pawsey
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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Affiliation(s)
- Rashida N. Smith
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
| | - Linda Reven
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
| | - Christopher J. Barrett
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada
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Walter TH, Reven L, Oldfield E. Magic-angle spinning carbon-13 NMR spectroscopy of transition-metal carbonyl clusters. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100341a029] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Reven L, Oldfield E. Carbon-13 nuclear magnetic resonance spectroscopic study of dodecacarbonyltriiron and -triruthenium supported on metal oxide surfaces. Inorg Chem 2002. [DOI: 10.1021/ic00028a023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Long HW, Gaede HC, Shore J, Reven L, Bowers CR, Kritzenberger J, Pietrass T, Pines A, Tang P, Reimer JA. High-field cross polarization NMR from laser-polarized xenon to a polymer surface. J Am Chem Soc 2002. [DOI: 10.1021/ja00071a086] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Buffington L, Crusius J, Nachbor M, Reven L. Dependence on anomeric configuration of the temperature dependence of the chemical shifts of exchangeable protons of pyranoses and pyranosides. J Am Chem Soc 2002. [DOI: 10.1021/ja00360a050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Yim CT, Pawsey S, Morin FG, Reven L. Dynamics of Octadecylphosphonate Monolayers Self-Assembled on Zirconium Oxide: A Deuterium NMR Study. J Phys Chem B 2002. [DOI: 10.1021/jp013649e] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. T. Yim
- Department of Chemistry, Dawson College, 3040 Sherbrooke Street West, Westmount, Québec, Canada H3Z 1A4
| | - S. Pawsey
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - F. G. Morin
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - L. Reven
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
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39
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Affiliation(s)
- Victor Nasreddine
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - Jamie Halla
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - Linda Reven
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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Abstract
In this Account, we discuss the dynamic features of self-assembled monolayers (SAMs) on both planar and nonplanar substrates. Our focus is on organothiol and organic acid-based monolayers. Results from variable-temperature electrochemical, calorimetric, vibrational, and solid-state NMR spectroscopic measurements lead to a convergent description of SAM dynamics.
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Affiliation(s)
- A Badia
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 2K6 Canada.
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Schmitt H, Badia A, Dickinson L, Reven L, Lennox RB. The Effect of Terminal Hydrogen Bonding on the Structure and Dynamics of Nanoparticle Self-Assembled Monolayers (SAMs): An NMR Dynamics Study. Adv Mater 1998; 10:475-480. [PMID: 21647982 DOI: 10.1002/(sici)1521-4095(199804)10:6<475::aid-adma475>3.0.co;2-i] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- H Schmitt
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 2K6 (Canada)
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Badia A, Demers L, Dickinson L, Morin FG, Lennox RB, Reven L. Gold−Sulfur Interactions in Alkylthiol Self-Assembled Monolayers Formed on Gold Nanoparticles Studied by Solid-State NMR. J Am Chem Soc 1997. [DOI: 10.1021/ja9726163] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Badia
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal, Quebec, Canada H3A 2K6
| | - L. Demers
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal, Quebec, Canada H3A 2K6
| | - L. Dickinson
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal, Quebec, Canada H3A 2K6
| | - F. G. Morin
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal, Quebec, Canada H3A 2K6
| | - R. B. Lennox
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal, Quebec, Canada H3A 2K6
| | - L. Reven
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal, Quebec, Canada H3A 2K6
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Reven L, Shore J, Yang S, Duncan T, Schwartz D, Chung J, Oldfield E. 17O nuclear-magnetic-resonance spin-lattice relaxation and Knight-shift behavior in bismuthate, plumbate, and cuprate superconductors. Phys Rev B Condens Matter 1991; 43:10466-10471. [PMID: 9996771 DOI: 10.1103/physrevb.43.10466] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Raftery D, Long H, Meersmann T, Grandinetti PJ, Reven L, Pines A. High-field NMR of adsorbed xenon polarized by laser pumping. Phys Rev Lett 1991; 66:584-587. [PMID: 10043847 DOI: 10.1103/physrevlett.66.584] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
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46
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Oldfield E, Coretsopoulos C, Yang S, Reven L, Lee HC, Shore J, Han OH, Ramli E, Hinks D. 17O nuclear-magnetic-resonance spectroscopic study of high-Tc superconductors. Phys Rev B Condens Matter 1989; 40:6832-6849. [PMID: 9991058 DOI: 10.1103/physrevb.40.6832] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Coretsopoulos C, Lee HC, Ramli E, Reven L, Rauchfuss TB, Oldfield E. 17O NMR spectroscopy of magnetically ordered YBa2Cu3O7-x microcrystals. Phys Rev B Condens Matter 1989; 39:781-784. [PMID: 9947231 DOI: 10.1103/physrevb.39.781] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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