1
|
Jundale RB, Bari AH, Kulkarni AA. Insights into the Synthesis and Kinetics of Silver-on-Silica Core-Shell Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37399513 DOI: 10.1021/acs.langmuir.3c00624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
In this study, a heterogeneous nucleation and growth model has been developed to explore the formation mechanism of silver-deposited silica core-shell particles based on the reaction kinetics. To validate the core-shell model, the time-dependent experimental data were quantitatively examined and in situ reduction, nucleation, and growth rates were estimated by optimizing the concentration profiles of reactants and deposited silver particles. Using this model, we also attempted to predict the change in the surface area and diameter of core-shell particles. The concentration of the reducing agent, metal precursor, and reaction temperature were found to have a strong influence on the rate constants and morphology of core-shell particles. Higher rates of nucleation and growth often produced thick, asymmetric patches that covered the entire surface, whereas lower rates produced sparsely deposited silver particles with a spherical shape. The result revealed that by simply tuning the process parameters and controlling the relative rates, the morphology of deposited silver particles and the surface coverage can be controlled while retaining the spherical shape of the core. The present study aims to offer comprehensive data pertaining to the nucleation, growth, and coalescence processes of core-shell nanostructures which will aid in the development and understanding of the principles that govern the formation of nanoparticle-coated materials.
Collapse
Affiliation(s)
- Rajashri B Jundale
- Chemical Engineering & Process Development Division, CSIR-National Chemical Laboratory, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Atul H Bari
- Chemical Engineering & Process Development Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Amol A Kulkarni
- Chemical Engineering & Process Development Division, CSIR-National Chemical Laboratory, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
2
|
Swift T. Stabilisation of acrylic latexes containing silica nanoparticles for dirt repellent coating applications. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
|
3
|
Ober MF, Baptist A, Wassermann L, Heuer-Jungemann A, Nickel B. In situ small-angle X-ray scattering reveals strong condensation of DNA origami during silicification. Nat Commun 2022; 13:5668. [PMID: 36167861 PMCID: PMC9515200 DOI: 10.1038/s41467-022-33083-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/31/2022] [Indexed: 11/09/2022] Open
Abstract
Silicification of DNA origami structures increases their stability and provides chemical protection. Yet, it is unclear whether the whole DNA framework is embedded or if silica just forms an outer shell and how silicification affects the origami's internal structure. Employing in situ small-angle X-ray scattering (SAXS), we show that addition of silica precursors induces substantial condensation of the DNA origami at early reaction times by almost 10 %. Subsequently, the overall size of the silicified DNA origami increases again due to increasing silica deposition. We further identify the SAXS Porod invariant as a reliable, model-free parameter for the evaluation of the amount of silica formation at a given time. Contrast matching of the DNA double helix Lorentzian peak reveals silica growth also inside the origami. The less polar silica forming within the origami structure, replacing more than 40 % of the internal hydration water, causes a hydrophobic effect: condensation. DNA origami objects with flat surfaces show a strong tendency towards aggregation during silicification, presumably driven by the same entropic forces causing condensation. Maximally condensed origami displayed thermal stability up to 60 °C. Our studies provide insights into the silicification reaction allowing for the formulation of optimized reaction protocols.
Collapse
Affiliation(s)
- Martina F Ober
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539, Munich, Germany
| | - Anna Baptist
- Max Planck Institute of Biochemistry and CeNS, Ludwig-Maximilians-Universität München, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Lea Wassermann
- Max Planck Institute of Biochemistry and CeNS, Ludwig-Maximilians-Universität München, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Amelie Heuer-Jungemann
- Max Planck Institute of Biochemistry and CeNS, Ludwig-Maximilians-Universität München, Am Klopferspitz 18, 82152, Martinsried, Germany.
| | - Bert Nickel
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539, Munich, Germany.
| |
Collapse
|
4
|
Czajka A, Liao G, Mykhaylyk OO, Armes SP. In situ small-angle X-ray scattering studies during the formation of polymer/silica nanocomposite particles in aqueous solution. Chem Sci 2021; 12:14288-14300. [PMID: 34760215 PMCID: PMC8565378 DOI: 10.1039/d1sc03353k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/04/2021] [Indexed: 11/30/2022] Open
Abstract
This study is focused on the formation of polymer/silica nanocomposite particles prepared by the surfactant-free aqueous emulsion polymerization of 2,2,2-trifluoroethyl methacrylate (TFEMA) in the presence of 19 nm glycerol-functionalized aqueous silica nanoparticles using a cationic azo initiator at 60 °C. The TFEMA polymerization kinetics are monitored using 1H NMR spectroscopy, while postmortem TEM analysis confirms that the final nanocomposite particles possess a well-defined core-shell morphology. Time-resolved small-angle X-ray scattering (SAXS) is used in conjunction with a stirrable reaction cell to monitor the evolution of the nanocomposite particle diameter, mean silica shell thickness, mean number of silica nanoparticles within the shell, silica aggregation efficiency and packing density during the TFEMA polymerization. Nucleation occurs after 10-15 min and the nascent particles quickly become swollen with TFEMA monomer, which leads to a relatively fast rate of polymerization. Additional surface area is created as these initial particles grow and anionic silica nanoparticles adsorb at the particle surface to maintain a relatively high surface coverage and hence ensure colloidal stability. At high TFEMA conversion, a contiguous silica shell is formed and essentially no further adsorption of silica nanoparticles occurs. A population balance model is introduced into the SAXS model to account for the gradual incorporation of the silica nanoparticles within the nanocomposite particles. The final PTFEMA/silica nanocomposite particles are obtained at 96% TFEMA conversion after 140 min, have a volume-average diameter of 216 ± 9 nm and contain approximately 274 silica nanoparticles within their outer shells; a silica aggregation efficiency of 75% can be achieved for such formulations.
Collapse
Affiliation(s)
- A Czajka
- Department of Chemistry, University of Sheffield Dainton Building, Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - G Liao
- Department of Chemistry, University of Sheffield Dainton Building, Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - O O Mykhaylyk
- Department of Chemistry, University of Sheffield Dainton Building, Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - S P Armes
- Department of Chemistry, University of Sheffield Dainton Building, Brook Hill Sheffield South Yorkshire S3 7HF UK
| |
Collapse
|
5
|
Chan DH, Kynaston EL, Lindsay C, Taylor P, Armes SP. Block Copolymer Nanoparticles are Effective Dispersants for Micrometer-Sized Organic Crystalline Particles. ACS APPLIED MATERIALS & INTERFACES 2021; 13:30235-30243. [PMID: 34151553 PMCID: PMC8289232 DOI: 10.1021/acsami.1c08261] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/09/2021] [Indexed: 05/08/2023]
Abstract
Well-defined sterically stabilized diblock copolymer nanoparticles of 29 nm diameter are prepared by RAFT aqueous emulsion polymerization of methyl methacrylate using a dithiobenzoate-capped poly(glycerol monomethacrylate) precursor. These nanoparticles are evaluated as a dispersant for the preparation of organic crystalline microparticles via ball milling. This is exemplified for azoxystrobin, which is a broad-spectrum fungicide that is widely used to protect various food crops. Laser diffraction and optical microscopy studies indicate the formation of azoxystrobin microparticles of approximately 2 μm diameter after ball milling for 10 min at 400 rpm. Nanoparticle adsorption at the surface of these azoxystrobin microparticles is confirmed by electron microscopy studies. The extent of nanoparticle adsorption on the azoxystrobin microparticles can be quantified using a supernatant assay based on solution densitometry. This technique indicates an adsorbed amount of approximately 5.5 mg m-2, which is sufficient to significantly reduce the negative zeta potential exhibited by azoxystrobin. Moreover, this adsorbed amount appears to be essentially independent of the nature of the core-forming block, with similar data being obtained for both poly(methyl methacrylate)- and poly(2,2,2-trifluoroethyl methacrylate)-based nanoparticles. Finally, X-ray photoelectron spectroscopy studies confirm attenuation of the underlying N1s signal arising from the azoxystrobin microparticles by the former adsorbed nanoparticles, suggesting a fractional surface coverage of approximately 0.24. This value is consistent with a theoretical surface coverage of 0.25 calculated from the adsorption isotherm data. Overall, this study suggests that sterically stabilized diblock copolymer nanoparticles may offer a useful alternative approach to traditional soluble copolymer dispersants for the preparation of suspension concentrates affecting the context of agrochemical applications.
Collapse
Affiliation(s)
- Derek
H. H. Chan
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, U.K.
| | - Emily L. Kynaston
- Syngenta,
Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, U.K.
| | - Christopher Lindsay
- Syngenta,
Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, U.K.
| | - Philip Taylor
- Syngenta,
Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, U.K.
| | - Steven P. Armes
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, U.K.
| |
Collapse
|
6
|
Smith AJ, Alcock SG, Davidson LS, Emmins JH, Hiller Bardsley JC, Holloway P, Malfois M, Marshall AR, Pizzey CL, Rogers SE, Shebanova O, Snow T, Sutter JP, Williams EP, Terrill NJ. I22: SAXS/WAXS beamline at Diamond Light Source - an overview of 10 years operation. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:939-947. [PMID: 33950002 PMCID: PMC8127364 DOI: 10.1107/s1600577521002113] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 02/23/2021] [Indexed: 05/04/2023]
Abstract
Beamline I22 at Diamond Light Source is dedicated to the study of soft-matter systems from both biological and materials science. The beamline can operate in the range 3.7 keV to 22 keV for transmission SAXS and 14 keV to 20 keV for microfocus SAXS with beam sizes of 240 µm × 60 µm [full width half-maximum (FWHM) horizontal (H) × vertical (V)] at the sample for the main beamline, and approximately 10 µm × 10 µm for the dedicated microfocusing platform. There is a versatile sample platform for accommodating a range of facilities and user-developed sample environments. The high brilliance of the insertion device source on I22 allows structural investigation of materials under extreme environments (for example, fluid flow at high pressures and temperatures). I22 provides reliable access to millisecond data acquisition timescales, essential to understanding kinetic processes such as protein folding or structural evolution in polymers and colloids.
Collapse
Affiliation(s)
- A. J. Smith
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - S. G. Alcock
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - L. S. Davidson
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - J. H. Emmins
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - J. C. Hiller Bardsley
- King’s College London, Guy’s Campus, Great Maze Pond, London SE1 1UL, United Kingdom
| | - P. Holloway
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - M. Malfois
- ALBA Synchrotron, Carrer de la Llum 2-26, 08290 Cerdanyola del Vallès, Barcelona, Spain
| | - A. R. Marshall
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - C. L. Pizzey
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - S. E. Rogers
- ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - O. Shebanova
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - T. Snow
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - J. P. Sutter
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - E. P. Williams
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - N. J. Terrill
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| |
Collapse
|
7
|
Mansour Y, Battie Y, Naciri AE, Chaoui N. Monitoring the aspect ratio distribution of colloidal gold nanoparticles under pulsed-laser exposure. OPTICS EXPRESS 2020; 28:34501-34515. [PMID: 33182918 DOI: 10.1364/oe.399831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
We propose an advanced in situ extinction spectroscopy set up to investigate the dynamic of the fragmentation and reshaping processes of gold colloids during a ns-laser pulse exposure. The evolution of the aspect ratio distribution of gold nanorods (NRs) during the laser exposure is obtained by analyzing each spectra with the shape distributed effective medium theory. We demonstrate that the kinetics of NR shape transformation can be divided into two fluence regimes. At small fluence, the kinetic is limited by the NRs orientation, while at high fluence, the fragmentation rate is only limited by the probability of NRs to be located in the irradiated volume.
Collapse
|
8
|
Brotherton EE, Hatton FL, Cockram AA, Derry MJ, Czajka A, Cornel EJ, Topham PD, Mykhaylyk OO, Armes SP. In Situ Small-Angle X-ray Scattering Studies During Reversible Addition-Fragmentation Chain Transfer Aqueous Emulsion Polymerization. J Am Chem Soc 2019; 141:13664-13675. [PMID: 31364361 PMCID: PMC6716212 DOI: 10.1021/jacs.9b06788] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Indexed: 11/29/2022]
Abstract
Polymerization-induced self-assembly (PISA) is a powerful platform technology for the rational and efficient synthesis of a wide range of block copolymer nano-objects (e.g., spheres, worms or vesicles) in various media. In situ small-angle X-ray scattering (SAXS) studies of reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization have previously provided detailed structural information during self-assembly (see M. J. Derry et al., Chem. Sci. 2016 , 7 , 5078 - 5090 ). However, conducting the analogous in situ SAXS studies during RAFT aqueous emulsion polymerizations poses a formidable technical challenge because the inherently heterogeneous nature of such PISA formulations requires efficient stirring to generate sufficiently small monomer droplets. In the present study, the RAFT aqueous emulsion polymerization of 2-methoxyethyl methacrylate (MOEMA) has been explored for the first time. Chain extension of a relatively short non-ionic poly(glycerol monomethacrylate) (PGMA) precursor block leads to the formation of sterically-stabilized PGMA-PMOEMA spheres, worms or vesicles, depending on the precise reaction conditions. Construction of a suitable phase diagram enables each of these three morphologies to be reproducibly targeted at copolymer concentrations ranging from 10 to 30% w/w solids. High MOEMA conversions are achieved within 2 h at 70 °C, which makes this new PISA formulation well-suited for in situ SAXS studies using a new reaction cell. This bespoke cell enables efficient stirring and hence allows in situ monitoring during RAFT emulsion polymerization for the first time. For example, the onset of micellization and subsequent evolution in particle size can be studied when preparing PGMA29-PMOEMA30 spheres at 10% w/w solids. When targeting PGMA29-PMOEMA70 vesicles under the same conditions, both the micellar nucleation event and the subsequent evolution in the diblock copolymer morphology from spheres to worms to vesicles are observed. These new insights significantly enhance our understanding of the PISA mechanism during RAFT aqueous emulsion polymerization.
Collapse
Affiliation(s)
- Emma E. Brotherton
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Fiona L. Hatton
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Amy A. Cockram
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Matthew J. Derry
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Adam Czajka
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Erik J. Cornel
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Paul D. Topham
- Aston Institute of
Materials Research, Aston University, Birmingham B4 7ET, United Kingdom
| | - Oleksandr O. Mykhaylyk
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Steven P. Armes
- Dainton Building,
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| |
Collapse
|
9
|
da Luz RC, Paixão MV, de C. Balaban R. Nanosilica-chitosan hybrid materials: Preparation, characterization and application in aqueous drilling fluids. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.01.131] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
10
|
Lan Y, Liu J, Eiser E, Scherman OA. Polymeric raspberry-like particles via template-assisted polymerisation. Polym Chem 2019. [DOI: 10.1039/c9py00484j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Functional monodisperse raspberry-like colloids are fabricated via template-assisted polymerisation, leading to optical materials with high dispersion stability in an aqueous environment.
Collapse
Affiliation(s)
- Yang Lan
- Melville Laboratory for Polymer Synthesis
- Department of Chemistry
- University of Cambridge
- Cambridge CB2 1EW
- UK
| | - Ji Liu
- Melville Laboratory for Polymer Synthesis
- Department of Chemistry
- University of Cambridge
- Cambridge CB2 1EW
- UK
| | - Erika Eiser
- Cavendish Laboratory
- University of Cambridge
- Cambridge CB3 0HE
- UK
| | - Oren A. Scherman
- Melville Laboratory for Polymer Synthesis
- Department of Chemistry
- University of Cambridge
- Cambridge CB2 1EW
- UK
| |
Collapse
|
11
|
Han H, Li L, Wang W, Tian Y, Wang Y, Wang J, von Klitzing R, Guo X. Core-Shell-Corona Silica Hybrid Nanoparticles Templated by Spherical Polyelectrolyte Brushes: A Study by Small Angle X-ray Scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:9857-9865. [PMID: 28836791 DOI: 10.1021/acs.langmuir.7b02239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Core-shell-corona silica/polymer hybrid nanoparticles with narrow size distribution were prepared in the template of spherical polyelectrolyte brushes (SPB) which consist of a solid polystyrene (PS) core densely grafted with linear poly(acrylic acid) (PAA) chains. The microstructure of obtained hybrid nanoparticles was studied by small-angle X-ray scattering (SAXS) and in combination with dynamic light scattering (DLS) and transmission electron microscopy (TEM). The generation of silica shell within the brush is confirmed by the significant increase of the electron density in the shell, and the silica shell showed a unique inner-loose-outer-dense structure, whose thickness is pH sensitive but is insensitive to ionic strength as revealed by fitting SAXS data. After dissolving the PS core, hollow silica nanoparticles were obtained and determined by SAXS, which should be ideal carriers for pH-triggered drug delivery. SAXS is confirmed to be a powerful method to characterize the core-shell-corona silica/polymer hybrid and hollow silica nanoparticles.
Collapse
Affiliation(s)
- Haoya Han
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology , 200237 Shanghai, P.R. China
- Department of Physics, Technical University Darmstadt , Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
| | - Li Li
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology , 200237 Shanghai, P.R. China
| | - Weihua Wang
- Sinopec Shanghai Research Institute of Petrochemical Technology , 201208 Shanghai, P.R. China
| | - Yuchuan Tian
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology , 200237 Shanghai, P.R. China
| | - Yunwei Wang
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology , 200237 Shanghai, P.R. China
| | - Junyou Wang
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology , 200237 Shanghai, P.R. China
| | - Regine von Klitzing
- Department of Physics, Technical University Darmstadt , Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
| | - Xuhong Guo
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology , 200237 Shanghai, P.R. China
- Engineering Research Center of Materials Chemical Engineering of Xinjiang Bingtuan, Shihezi University , 832000 Xinjiang, P.R. China
| |
Collapse
|
12
|
Vogiatzis GG, Theodorou DN. Multiscale Molecular Simulations of Polymer-Matrix Nanocomposites: or What Molecular Simulations Have Taught us About the Fascinating Nanoworld. ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING : STATE OF THE ART REVIEWS 2017; 25:591-645. [PMID: 29962833 PMCID: PMC6003436 DOI: 10.1007/s11831-016-9207-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 06/08/2023]
Abstract
Following the substantial progress in molecular simulations of polymer-matrix nanocomposites, now is the time to reconsider this topic from a critical point of view. A comprehensive survey is reported herein providing an overview of classical molecular simulations, reviewing their major achievements in modeling polymer matrix nanocomposites, and identifying several open challenges. Molecular simulations at multiple length and time scales, working hand-in-hand with sensitive experiments, have enhanced our understanding of how nanofillers alter the structure, dynamics, thermodynamics, rheology and mechanical properties of the surrounding polymer matrices.
Collapse
Affiliation(s)
- Georgios G. Vogiatzis
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
- Present Address: Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
| |
Collapse
|
13
|
Zou H, Wang X. Adsorption of Silica Nanoparticles onto Poly(N-vinylpyrrolidone)-Functionalized Polystyrene Latex. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1471-1477. [PMID: 28112949 DOI: 10.1021/acs.langmuir.6b03977] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This paper presents a more general method to prepare silica-coated polystyrene (PS) particles with minimal excess silica by adsorption, highlighting the role of poly(N-vinylpyrrolidone) (PVP). The method is based on the addition of small silica nanoparticles onto submicrometer-sized near-monodisperse polymer latex particles under the conditions of monolayer silica coverage of the latex surface. Either a cationic or an anionic initiator could be used in the PVP-involved emulsion polymerization to prepare PS particles, and the adsorption was conducted successfully either under acidic or basic conditions. Neither a cationic initiator nor a basic condition is a prerequisite for the adsorption process, which should be related to the much stronger interaction between PVP and the silica surface. This method is expected to substantially extend the adsorption conditions of polymer-silica colloidal nanocomposite syntheses.
Collapse
Affiliation(s)
- Hua Zou
- School of Materials Science and Engineering, University of Shanghai for Science and Technology , 516 Jungong Road, Shanghai 200093, China
| | - Xia Wang
- School of Materials Science and Engineering, University of Shanghai for Science and Technology , 516 Jungong Road, Shanghai 200093, China
| |
Collapse
|
14
|
North SM, Jones ER, Smith GN, Mykhaylyk OO, Annable T, Armes SP. Adsorption of Small Cationic Nanoparticles onto Large Anionic Particles from Aqueous Solution: A Model System for Understanding Pigment Dispersion and the Problem of Effective Particle Density. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1275-1284. [PMID: 28075595 PMCID: PMC5299546 DOI: 10.1021/acs.langmuir.6b04541] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/11/2017] [Indexed: 05/24/2023]
Abstract
The present study focuses on the use of copolymer nanoparticles as a dispersant for a model pigment (silica). Reversible addition-fragmentation chain transfer (RAFT) alcoholic dispersion polymerization was used to synthesize sterically stabilized diblock copolymer nanoparticles. The steric stabilizer block was poly(2-(dimethylamino)ethyl methacrylate) (PDMA) and the core-forming block was poly(benzyl methacrylate) (PBzMA). The mean degrees of polymerization for the PDMA and PBzMA blocks were 71 and 100, respectively. Transmission electron microscopy (TEM) studies confirmed a near-monodisperse spherical morphology, while dynamic light scattering (DLS) studies indicated an intensity-average diameter of 30 nm. Small-angle X-ray scattering (SAXS) reported a volume-average diameter of 29 ± 0.5 nm and a mean aggregation number of 154. Aqueous electrophoresis measurements confirmed that these PDMA71-PBzMA100 nanoparticles acquired cationic character when transferred from ethanol to water as a result of protonation of the weakly basic PDMA chains. Electrostatic adsorption of these nanoparticles from aqueous solution onto 470 nm silica particles led to either flocculation at submonolayer coverage or steric stabilization at or above monolayer coverage, as judged by DLS. This technique indicated that saturation coverage was achieved on addition of approximately 465 copolymer nanoparticles per silica particle, which corresponds to a fractional surface coverage of around 0.42. These adsorption data were corroborated using thermogravimetry, UV spectroscopy and X-ray photoelectron spectroscopy. TEM studies indicated that the cationic nanoparticles remained intact on the silica surface after electrostatic adsorption, while aqueous electrophoresis confirmed that surface charge reversal occurred below pH 7. The relatively thick layer of adsorbed nanoparticles led to a significant reduction in the effective particle density of the silica particles from 1.99 g cm-3 to approximately 1.74 g cm-3, as judged by disk centrifuge photosedimentometry (DCP). Combining the DCP and SAXS data suggests that essentially no deformation of the PBzMA cores occurs during nanoparticle adsorption onto the silica particles.
Collapse
Affiliation(s)
- S. M. North
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| | - E. R. Jones
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| | - G. N. Smith
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| | - O. O. Mykhaylyk
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| | - T. Annable
- Lubrizol
Limited, Hexagon Tower, P.O. Box 42, Blackley, Manchester M9
8ZS, U.K.
| | - S. P. Armes
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| |
Collapse
|
15
|
Han H, Li L, Tian Y, Wang Y, Ye Z, Yang Q, Wang Y, von Klitzing R, Guo X. Spherical polyelectrolyte nanogels as templates to prepare hollow silica nanocarriers: observation by small angle X-ray scattering and TEM. RSC Adv 2017. [DOI: 10.1039/c7ra10011f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Hollow silica nanoparticles were prepared through generating a silica layer in spherical polyelectrolyte nanogels, which consisted of a solid core of polystyrene and a shell of crosslinked poly(acrylic acid), followed by removing the core via solvent dissolution.
Collapse
Affiliation(s)
- Haoya Han
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
| | - Li Li
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
| | - Yuchuan Tian
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
| | - Yunwei Wang
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
| | - Zhishuang Ye
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
| | - Qingsong Yang
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
| | - Yiming Wang
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
- Department of Chemical Engineering
| | | | - Xuhong Guo
- State Key Laboratory of Chemical Engineering
- East China University of Science and Technology
- 200237 Shanghai
- P. R. China
- Engineering Research Center of Materials Chemical Engineering of Xinjiang Bingtuan
| |
Collapse
|
16
|
da Silva J, de Souza S, Trovati G, Sanches E. Chloride salt of conducting polyaniline synthesized in the presence of CeO2: Structural analysis of the core-shell nanocomposite. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.07.114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
17
|
Affiliation(s)
- Daniel F. Sunday
- Department
of Chemical Engineering, University of Virginia, 102 Engineers Way, Charlottesville, Virginia 22904, United States
| | - David L. Green
- Department
of Chemical Engineering, University of Virginia, 102 Engineers Way, Charlottesville, Virginia 22904, United States
| |
Collapse
|
18
|
Warren N, Armes SP. Polymerization-induced self-assembly of block copolymer nano-objects via RAFT aqueous dispersion polymerization. J Am Chem Soc 2014; 136:10174-85. [PMID: 24968281 PMCID: PMC4111214 DOI: 10.1021/ja502843f] [Citation(s) in RCA: 790] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Indexed: 12/17/2022]
Abstract
In this Perspective, we discuss the recent development of polymerization-induced self-assembly mediated by reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization. This approach has quickly become a powerful and versatile technique for the synthesis of a wide range of bespoke organic diblock copolymer nano-objects of controllable size, morphology, and surface functionality. Given its potential scalability, such environmentally-friendly formulations are expected to offer many potential applications, such as novel Pickering emulsifiers, efficient microencapsulation vehicles, and sterilizable thermo-responsive hydrogels for the cost-effective long-term storage of mammalian cells.
Collapse
Affiliation(s)
- Nicholas
J. Warren
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield, Yorkshire S3
7HF, U.K.
| | - Steven P. Armes
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield, Yorkshire S3
7HF, U.K.
| |
Collapse
|
19
|
Fielding LA, Armes SP, Staniland P, Sayer R, Tooley I. Physical adsorption of anisotropic titania nanoparticles onto poly(2-vinylpyridine) latex and characterisation of the resulting nanocomposite particles. J Colloid Interface Sci 2014; 426:170-80. [PMID: 24863780 DOI: 10.1016/j.jcis.2014.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 03/27/2014] [Accepted: 04/01/2014] [Indexed: 10/25/2022]
Abstract
Four poly(2-vinylpyridine) latexes with intensity-average mean diameters ranging between 246 and 955nm were prepared by aqueous emulsion polymerisation. These latexes were characterised by transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, aqueous electrophoresis, disc centrifuge photosedimentometry and thermogravimetry. The adsorption of rice grain-shaped nano-sized titania particles onto the surface of these latex particles from aqueous solution was investigated. It was found that the titania particles adsorb strongly at pH 10 and the optimal loading and packing density of titania was investigated for each latex. The resulting core-shell P2VP-titania nanocomposite particles were characterised in terms of their titania contents, surface coverages and colloidal stabilities. UV-Vis spectra were recorded for the titania nanoparticles, the original P2VP latexes and the poly(2-vinylpyridine)-titania nanocomposite particles. It was found that, for the larger nanocomposite particles, UV-Vis absorption was dominated by the latex core, whereas the smaller P2VP-titania nanocomposite particles exhibited UV attenuation to longer wavelengths compared to both the bare latex and the titania particles. The poly(2-vinylpyridine) cores were selectively removed by calcination of the nanocomposite particles and the resulting hollow titania structures were investigated by transmission electron microscopy.
Collapse
Affiliation(s)
- Lee A Fielding
- Dainton Building, Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, UK.
| | - Steven P Armes
- Dainton Building, Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, UK
| | - Paul Staniland
- Croda Europe Ltd., Foundry Lane, Ditton, Widnes, Cheshire WA8 8UB, UK
| | - Robert Sayer
- Croda Europe Ltd., Foundry Lane, Ditton, Widnes, Cheshire WA8 8UB, UK
| | - Ian Tooley
- Croda Europe Ltd., Foundry Lane, Ditton, Widnes, Cheshire WA8 8UB, UK
| |
Collapse
|
20
|
Nanomorphology characterization of sterically stabilized polypyrrole-palladium nanocomposite particles. Polym J 2014. [DOI: 10.1038/pj.2014.44] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
21
|
Fielding LA, Lane JA, Derry MJ, Mykhaylyk OO, Armes SP. Thermo-responsive diblock copolymer worm gels in non-polar solvents. J Am Chem Soc 2014; 136:5790-8. [PMID: 24678949 PMCID: PMC4015619 DOI: 10.1021/ja501756h] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Indexed: 12/17/2022]
Abstract
Benzyl methacrylate (BzMA) is polymerized using a poly(lauryl methacrylate) macromolecular chain transfer agent (PLMA macro-CTA) using reversible addition-fragmentation chain transfer (RAFT) polymerization at 70 °C in n-dodecane. This choice of solvent leads to an efficient dispersion polymerization, with polymerization-induced self-assembly (PISA) occurring via the growing PBzMA block to produce a range of PLMA-PBzMA diblock copolymer nano-objects, including spheres, worms, and vesicles. In the present study, particular attention is paid to the worm phase, which forms soft free-standing gels at 20 °C due to multiple inter-worm contacts. Such worm gels exhibit thermo-responsive behavior: heating above 50 °C causes degelation due to the onset of a worm-to-sphere transition. Degelation occurs because isotropic spheres interact with each other much less efficiently than the highly anisotropic worms. This worm-to-sphere thermal transition is essentially irreversible on heating a dilute solution (0.10% w/w) but is more or less reversible on heating a more concentrated dispersion (20% w/w). The relatively low volatility of n-dodecane facilitates variable-temperature rheological studies, which are consistent with eventual reconstitution of the worm phase on cooling to 20 °C. Variable-temperature (1)H NMR studies conducted in d26-dodecane confirm partial solvation of the PBzMA block at elevated temperature: surface plasticization of the worm cores is invoked to account for the observed change in morphology, because this is sufficient to increase the copolymer curvature and hence induce a worm-to-sphere transition. Small-angle X-ray scattering and TEM are used to investigate the structural changes that occur during the worm-to-sphere-to-worm thermal cycle; experiments conducted at 1.0 and 5.0% w/w demonstrate the concentration-dependent (ir)reversibility of these morphological transitions.
Collapse
Affiliation(s)
- Lee A. Fielding
- Dainton Building, Department
of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Jacob A. Lane
- Dainton Building, Department
of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Matthew J. Derry
- Dainton Building, Department
of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Oleksandr O. Mykhaylyk
- Dainton Building, Department
of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Steven P. Armes
- Dainton Building, Department
of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| |
Collapse
|
22
|
Lan Y, Wu Y, Karas A, Scherman OA. Photoresponsive Hybrid Raspberry-Like Colloids Based on Cucurbit[8]uril Host-Guest Interactions. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201309204] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
23
|
Lan Y, Wu Y, Karas A, Scherman OA. Photoresponsive Hybrid Raspberry-Like Colloids Based on Cucurbit[8]uril Host-Guest Interactions. Angew Chem Int Ed Engl 2014; 53:2166-9. [DOI: 10.1002/anie.201309204] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Indexed: 12/22/2022]
|
24
|
Roger K, Botet R, Cabane B. Coalescence of repelling colloidal droplets: a route to monodisperse populations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5689-5700. [PMID: 23570451 DOI: 10.1021/la400498j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Populations of droplets or particles dispersed in a liquid may evolve through Brownian collisions, aggregation, and coalescence. We have found a set of conditions under which these populations evolve spontaneously toward a narrow size distribution. The experimental system consists of poly(methyl methacrylate) (PMMA) nanodroplets dispersed in a solvent (acetone) + nonsolvent (water) mixture. These droplets carry electrical charges, located on the ionic end groups of the macromolecules. We used time-resolved small angle X-ray scattering to determine their size distribution. We find that the droplets grow through coalescence events: the average radius (R) increases logarithmically with elapsed time while the relative width σR/(R) of the distribution decreases as the inverse square root of (R). We interpret this evolution as resulting from coalescence events that are hindered by ionic repulsions between droplets. We generalize this evolution through a simulation of the Smoluchowski kinetic equation, with a kernel that takes into account the interactions between droplets. In the case of vanishing or attractive interactions, all droplet encounters lead to coalescence. The corresponding kernel leads to the well-known "self-preserving" particle distribution of the coalescence process, where σR/(R) increases to a plateau value. However, for droplets that interact through long-range ionic repulsions, "large + small" droplet encounters are more successful at coalescence than "large + large" encounters. We show that the corresponding kernel leads to a particular scaling of the droplet-size distribution-known as the "second-scaling law" in the theory of critical phenomena, where σR/(R) decreases as 1/√(R) and becomes independent of the initial distribution. We argue that this scaling explains the narrow size distributions of colloidal dispersions that have been synthesized through aggregation processes.
Collapse
|
25
|
Au KM, Armes SP. Heterocoagulation as a facile route to prepare stable serum albumin-nanoparticle conjugates for biomedical applications: synthetic protocols and mechanistic insights. ACS NANO 2012; 6:8261-8279. [PMID: 22913736 DOI: 10.1021/nn302968j] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
There is increasing interest in using serum albumin, the most abundant plasma protein, as a stabilizing agent in the context of nanomedicine. Using poly(vinyl amine)-stabilized polypyrrole nanoparticles as an example, we report a facile generic route to prepare serum albumin-nanoparticle conjugates via heterocoagulation. Time-resolved dynamic light scattering (DLS), disk centrifuge photosedimentometry (DCP), and circular dichroism (CD) spectroscopy studies confirm that bovine serum albumin (BSA) adsorbs rapidly onto the cationic poly(vinyl amine)-stabilized polypyrrole nanoparticles and suggest that the initial well-defined protein coronal is subsequently cross-linked via thiol-disulfide exchange. These BSA-nanoparticle conjugates were further characterized by X-ray photoelectron spectroscopy (XPS), aqueous electrophoresis, field emission scanning electron microscopy (FE SEM), and transmission electron microscopy (TEM). They exhibit excellent long-term colloidal stability under physiological conditions without further purification, suggesting strong irreversible adsorption by the BSA. Protein adsorption appears to be co-operative and both thermodynamic and mechanistic aspects were examined via aqueous electrophoresis, DCP, and DLS studies.
Collapse
Affiliation(s)
- Kin Man Au
- Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, UK
| | | |
Collapse
|
26
|
Fielding LA, Mykhaylyk OO, Armes SP, Fowler PW, Mittal V, Fitzpatrick S. Correcting for a density distribution: particle size analysis of core-shell nanocomposite particles using disk centrifuge photosedimentometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:2536-2544. [PMID: 22214311 DOI: 10.1021/la204841n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Many types of colloidal particles possess a core-shell morphology. In this Article, we show that, if the core and shell densities differ, this morphology leads to an inherent density distribution for particles of finite polydispersity. If the shell is denser than the core, this density distribution implies an artificial narrowing of the particle size distribution as determined by disk centrifuge photosedimentometry (DCP). In the specific case of polystyrene/silica nanocomposite particles, which consist of a polystyrene core coated with a monolayer shell of silica nanoparticles, we demonstrate that the particle density distribution can be determined by analytical ultracentrifugation and introduce a mathematical method to account for this density distribution by reanalyzing the raw DCP data. Using the mean silica packing density calculated from small-angle X-ray scattering, the real particle density can be calculated for each data point. The corrected DCP particle size distribution is both broader and more consistent with particle size distributions reported for the same polystyrene/silica nanocomposite sample using other sizing techniques, such as electron microscopy, laser light diffraction, and dynamic light scattering. Artifactual narrowing of the size distribution is also likely to occur for many other polymer/inorganic nanocomposite particles comprising a low-density core of variable dimensions coated with a high-density shell of constant thickness, or for core-shell latexes where the shell is continuous rather than particulate in nature.
Collapse
Affiliation(s)
- Lee A Fielding
- Dainton Building, Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | | | | | | | | | | |
Collapse
|
27
|
Lee S, Vece MD, Lee B, Seifert S, Winans RE, Vajda S. Oxidative dehydrogenation of cyclohexene on size selected subnanometer cobalt clusters: improved catalytic performance via evolution of cluster-assembled nanostructures. Phys Chem Chem Phys 2012; 14:9336-42. [DOI: 10.1039/c2cp40162b] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
28
|
Balmer JA, Mykhaylyk OO, Schmid A, Armes SP, Fairclough JPA, Ryan AJ. Characterization of polymer-silica nanocomposite particles with core-shell morphologies using Monte Carlo simulations and small angle X-ray scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:8075-8089. [PMID: 21661736 DOI: 10.1021/la201319h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A two-population model based on standard small-angle X-ray scattering (SAXS) equations is verified for the analysis of core-shell structures comprising spherical colloidal particles with particulate shells. First, Monte Carlo simulations of core-shell structures are performed to demonstrate the applicability of the model. Three possible shell packings are considered: ordered silica shells due to either charge-dependent repulsive or size-dependent Lennard-Jones interactions or randomly arranged silica particles. In most cases, the two-population model produces an excellent fit to calculated SAXS patterns for the simulated core-shell structures, together with a good correlation between the fitting parameters and structural parameters used for the simulation. The limits of application are discussed, and then, this two-population model is applied to the analysis of well-defined core-shell vinyl polymer/silica nanocomposite particles, where the shell comprises a monolayer of spherical silica nanoparticles. Comprehensive SAXS analysis of a series of poly(styrene-co-n-butyl acrylate)/silica colloidal nanocomposite particles (prepared by the in situ emulsion copolymerization of styrene and n-butyl acrylate in the presence of a glycerol-functionalized silica sol) allows the overall core-shell particle diameter, the copolymer latex core diameter and polydispersity, the mean silica shell thickness, the mean silica diameter and polydispersity, the volume fractions of the two components, the silica packing density, and the silica shell structure to be obtained. These experimental SAXS results are consistent with electron microscopy, dynamic light scattering, thermogravimetry, helium pycnometry, and BET surface area studies. The high electron density contrast between the (co)polymer and the silica components, together with the relatively low polydispersity of these core-shell nanocomposite particles, makes SAXS ideally suited for the characterization of this system. Moreover, these results can be generalized for other types of core-shell colloidal particles.
Collapse
Affiliation(s)
- Jennifer A Balmer
- Dainton Building, Department of Chemistry, The University of Sheffield, Sheffield, Brook Hill, S3 7HF, United Kingdom
| | | | | | | | | | | |
Collapse
|
29
|
Fang FF, Liu YD, Lee IS, Choi HJ. Well controlled core/shell type polymeric microspheres coated with conducting polyaniline: fabrication and electrorheology. RSC Adv 2011. [DOI: 10.1039/c1ra00325a] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|