1
|
Aldakkan BS, Chalmpes N, Qi G, Hammami MA, Kanj MY, Giannelis EP. Synthesis of Raspberry-like Nanoparticles via Surface Grafting of Positively Charged Polyelectrolyte Brushes: Colloidal Stability and Surface Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5837-5849. [PMID: 38457691 DOI: 10.1021/acs.langmuir.3c03713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
A method to synthesize stable, raspberry-like nanoparticles (NPs), using surface grafting of poly(glycidyl methacrylate) (PGMA) brushes on a polystyrene (PS) core with varying grafting densities, is reported. A two-step functionalization reaction of PGMA epoxide groups comprising an amination step first using ethylene diamine and then followed by a quaternization using glycidyltrimethylammonium chloride generates permanently and positively charged polyelectrolyte brushes, which result in both steric and electrostatic stabilization. The dispersion stability of the brush-bearing NPs is dramatically improved compared to that of the pristine PS core in salt solutions at ambient (25 °C) and elevated temperatures (60 °C). Additionally, the grafted polyelectrolyte chains undergo a reversible swelling in the presence of different ionic strength (IS) salts, which modulate the surface properties, including roughness, stiffness, and adhesion. An atomic force microscope under both dry and wet conditions was used to image conformational changes of the polyelectrolyte chains during the swelling and deswelling transitions as well as to probe the nanomechanical properties by analyzing the corresponding force-sample separation curves. The quaternized polyelectrolyte brushes undergo a conformational transition from a collapsed state to a swelled state in the osmotic brush (OB) regime triggered by the osmotic gradient of mobile ions to the interior of the polymer chain. At IS ∼ 1 M, the brushes contract and the globules reform (salted brush state) as evidenced by an increase in the surface roughness and a reduction in the adhesion of the brushes. Beyond IS ∼ 1 M, quartz crystal microbalance with dissipation monitoring measurements show that salt uptake continues to take place predominantly on the exterior surface of the brush since salt adsorption is not accompanied by a size increase as measured by dynamic light scattering. The study adds new insights into our understanding of the behavior of NPs bearing salt-responsive polyelectrolyte brushes with adaptive swelling thresholds that can ultimately modulate surface properties.
Collapse
Affiliation(s)
- Bashayer Saad Aldakkan
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Nikolaos Chalmpes
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Genggeng Qi
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Mohamed Amen Hammami
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Mazen Yousef Kanj
- College of Petroleum Engineering & Geosciences, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| | - Emmanuel P Giannelis
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| |
Collapse
|
2
|
Gao J, Sugimoto T, Kobayashi M. Effects of ionic valence on aggregation kinetics of colloidal particles with and without a mixing flow. J Colloid Interface Sci 2023; 638:733-742. [PMID: 36780852 DOI: 10.1016/j.jcis.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 01/28/2023] [Accepted: 02/02/2023] [Indexed: 02/08/2023]
Abstract
HYPOTHESIS The classical Schulze-Hardy rule states that the critical coagulation concentration (CCC) of colloidal particles is inversely proportional to the counter-ionic valence at powers ranging from 2 to 6. However, the inverse Schulze-Hardy rule has recently been proposed, suggesting that the CCC can also be inversely proportional to the co-ionic valence. Previous studies on these rules did not consider the effect of flow on aggregation kinetics and the CCC. This study aims to investigate the effect of multivalent counter-ions and co-ions on aggregation kinetics and the CCCs in systems with and without a mixing flow. EXPERIMENTS We measured the aggregation rate coefficients of polystyrene sulfate latex particles as a function of the salt concentration with different ionic species. Furthermore, we analyzed these measurements using theoretical models based on hydrodynamic pair-diffusion in a random flow and trajectory analysis in two steady flows. The analysis was conducted using zeta potentials determined through electrophoretic measurements. FINDINGS Although the trajectory analysis underestimates the CCCs, the hydrodynamic pair-diffusion model can capture the shift of critical coagulation concentrations in the mixing flow to higher values than those in Brownian aggregation and also shows a better agreement with the experimental results. This result suggests that combining random flow and Brownian diffusion is crucial for developing a consistent framework for predicting both Brownian aggregation and aggregation in a mixing flow.
Collapse
Affiliation(s)
- Jiahui Gao
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan
| | - Takuya Sugimoto
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan.
| | - Motoyoshi Kobayashi
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan
| |
Collapse
|
3
|
Krucker-Velasquez E, Swan JW. Underscreening and hidden ion structures in large scale simulations of concentrated electrolytes. J Chem Phys 2021; 155:134903. [PMID: 34624965 DOI: 10.1063/5.0061230] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The electrostatic screening length predicted by Debye-Hückel theory decreases with increasing ionic strength, but recent experiments have found that the screening length can instead increase in concentrated electrolytes. This phenomenon, referred to as underscreening, is believed to result from ion-ion correlations and short-range forces such as excluded volume interactions among ions. We use Brownian Dynamics to simulate a version of the Restrictive Primitive Model for electrolytes over a wide range of ion concentrations, ionic strengths, and ion excluded volume radii for binary electrolytes. We measure the decay of the charge-charge correlation among ions in the bulk and compare it against scaling trends found experimentally and determined in certain weak coupling theories of ion-ion correlation. Moreover, we find that additional large scale ion structures emerge at high concentrations. In this regime, the frequency of oscillations computed from the charge-charge correlation function is not dominated by electrostatic interactions but rather by excluded volume interactions and with oscillation periods on the order of the ion diameter. We also find the nearest neighbor correlation of ions sharing the same charge transitions from negative at small concentrations to positive at high concentrations, representing the formation of small, like-charge ion clusters. We conclude that the increase in local charge density due to the formation of these clusters and the topological constraints of macroscopic charged surfaces can help explain the degree of underscreening observed experimentally.
Collapse
Affiliation(s)
- Emily Krucker-Velasquez
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - James W Swan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| |
Collapse
|
4
|
Smith GN, van Meurs S, Armes SP. The extent of counterion dissociation at the interface of cationic diblock copolymer nanoparticles in non-polar solvents. J Colloid Interface Sci 2020; 577:523-529. [PMID: 32534191 DOI: 10.1016/j.jcis.2020.04.102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 11/16/2022]
Abstract
HYPOTHESIS Diblock copolymer nanoparticles prepared in non-polar solvents that are sterically stabilized but possess ionic functionality from the inclusion of cationic comonomers in the stabilizer shell are known to exhibit complex electrokinetic behavior (Chem. Sci. 9 (2018) 922-934). For example, core-shell nanoparticles with cationic comonomers located solely within the shell layer have lower magnitude electrophoretic mobilities than nanoparticles containing the same cationic comonomers located within the core, whereas nanoparticles prepared using a minor fraction of steric stabilizer chains containing cationic comonomer repeat units have comparable electrophoretic mobilities to nanoparticles prepared with this cationic comonomer solely located within the core. We hypothesize that these observations can be explained in terms of the strength of the Coulombic interaction between counterions and the nanoparticle interface. EXPERIMENTS The highly-fluorinated anionic counterion associated with these cationic nanoparticles is studied by 19F nuclear magnetic resonance (NMR) spectroscopy in n-dodecane. This revealed only one type of 19F environment for a soluble macromolecular cation (the oil-soluble steric stabilizer chains used to prepare the nanoparticles), whereas two distinct environments were observed for the sterically-stabilized cationic nanoparticles. Both 19F diffusion NMR and 19F-13C heteronuclear single quantum correlation (HSQC) measurements support the existence of two environments for this counterion. FINDINGS The existence of two distinct 19F environments for the highly-fluorinated anion associated with the sterically-stabilized nanoparticles demonstrates the presence of spectroscopically distinguishable populations of ion pairs and of fully dissociated free anions. 19F NMR spectra recorded for sterically-stabilized nanoparticles with a fully ionic shell (all stabilizer chains containing the cationic comonomer) and those with a partly ionic shell (10% of stabilizer chains containing the cationic comonomer) reveal a higher proportion of dissociated anions in the partly ionic case. This suggests a stronger Coulombic interaction between counterions and the cationic interface when the shell is fully ionic, which accounts for the observed reduction in the magnitude of the electrophoretic mobility.
Collapse
Affiliation(s)
- Gregory N Smith
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom; Niels Bohr Institute, University of Copenhagen, H. C. Ørsted Institute, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
| | - Sandra van Meurs
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Steven P Armes
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| |
Collapse
|
5
|
Shaparenko NO, Kompan'kov NB, Demidova MG, Bulavchenko AI. Structure and conductivity of AOT solutions in n‐hexadecane‐chloroform mixtures. Electrophoresis 2020; 41:1592-1599. [DOI: 10.1002/elps.202000085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/30/2020] [Accepted: 07/22/2020] [Indexed: 11/11/2022]
|
6
|
Smith GN. Electrolytic conductivity of ionic polymers in a nonpolar solvent. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2020; 43:52. [PMID: 32743710 DOI: 10.1140/epje/i2020-11976-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
The electrolytic conductivity of two electrolytes as solutions in the nonpolar solvent, n -dodecane, as a function of concentration has been studied. One was a small molecule electrolyte (tetraalkyl cation and a highly fluorinated tetraphenylborate anion), and the other was a macromolecular electrolyte (cation-containing poly(alkyl methacrylate) chain with the same anion). Two series of the macromolecular cation were prepared: one with entirely cation-containing molecules and the other with a small proportion (10%) cation-containing and the rest nonionic. The conductivity data were qualitatively similar for all systems, which formed both single ions and triple ions. The data from the two series of macromolecular electrolytes were particularly informative to understand some recent and counterintuitive electrokinetic data for particles that were stabilized by these polymers. Reducing the proportion of cationic chains in the stabilizer of the particles was found to increase their electrophoretic mobility. In the conductivity data in this study, reducing the proportion of cationic chains in solution was found to increase the magnitude of the single-ion equilibrium constant and suppress the formation of triple ions. These data should support the development of models to understand these electrokinetic results.
Collapse
Affiliation(s)
- Gregory N Smith
- Department of Chemistry, University of Sheffield, Brook Hill, S3 7HF, Sheffield, South Yorkshire, UK.
| |
Collapse
|
7
|
Coupled Oxides/LLDPE Composites for Textile Effluent Treatment: Effect of Neem and PVA Stabilization. Polymers (Basel) 2020; 12:polym12020394. [PMID: 32050485 PMCID: PMC7077703 DOI: 10.3390/polym12020394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 02/06/2020] [Indexed: 11/29/2022] Open
Abstract
The polyvinyl alcohol (PVA) and neem extract were grafted onto coupled oxides (3ZT-CO) via reflux process to stabilize the particles to form 3ZT-CO/PVA and 3ZT-CO/Neem. These were then incorporated into LLDPE by melt blending process to give LLDPE/3ZT-CO/PVA and LLDPE/3ZT-CO/Neem composites. The Neem and PVA stabilized particles showed high zeta potential and dispersed homogeneously in water. The stabilization process altered the shape of the particles due to plane growth along the (002) polar direction. The stabilizers acted as capping agents and initiated the one-dimensional growth. The alkyl chain groups from PVA increased the polarity of the LLDPE/3ZT-CO/PVA and played a dominant role in the water adsorption process to activate the photocatalytic activity. This was further enhanced by the homogeneous distribution of the particles and low degree of crystallinity (20.87%) of the LLDPE composites. LLDPE/3ZT-CO/PVA exhibited the highest photodegradation (93.95%), which was better than the non-stabilized particles. Therefore, the photocatalytic activity of a polymer composite can be enhanced by grafting PVA and neem onto couple oxides. The LLDPE/3ZT-CO/PVA composite was further used to treat textile effluent. The results showed the composite was able to remove dye color by 93.95% and to reduce biochemical oxygen demand (BOD) and chemical oxygen demand (COD) by 99.99%.
Collapse
|
8
|
Bulavchenko AI, Shaparenko NO, Kompan’kov NB, Popovetskiy PS, Demidova MG, Arymbaeva AT. The formation of free ions and electrophoretic mobility of Ag and Au nanoparticles in n-hexadecane–chloroform mixtures at low concentrations of AOT. Phys Chem Chem Phys 2020; 22:14671-14681. [DOI: 10.1039/d0cp02153a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The electrophoretic mobility of Ag and Au nanoparticles in n-hexadecane–chloroform mixtures was studied as a function of the chloroform content (from 0 to 100 vol%).
Collapse
Affiliation(s)
| | - Nikita O. Shaparenko
- Nikolaev Institute of Inorganic Chemistry
- Russian Academy of Sciences
- Novosibirsk
- Russia
| | - Nikolay B. Kompan’kov
- Nikolaev Institute of Inorganic Chemistry
- Russian Academy of Sciences
- Novosibirsk
- Russia
| | - Pavel S. Popovetskiy
- Nikolaev Institute of Inorganic Chemistry
- Russian Academy of Sciences
- Novosibirsk
- Russia
| | - Marina G. Demidova
- Nikolaev Institute of Inorganic Chemistry
- Russian Academy of Sciences
- Novosibirsk
- Russia
| | - Aida T. Arymbaeva
- Nikolaev Institute of Inorganic Chemistry
- Russian Academy of Sciences
- Novosibirsk
- Russia
| |
Collapse
|
9
|
Smith GN, Derry MJ, Hallett JE, Lovett JR, Mykhaylyk OO, Neal TJ, Prévost S, Armes SP. Refractive index matched, nearly hard polymer colloids. Proc Math Phys Eng Sci 2019; 475:20180763. [PMID: 31293354 DOI: 10.1098/rspa.2018.0763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 05/09/2019] [Indexed: 11/12/2022] Open
Abstract
Refractive index matched particles serve as essential model systems for colloid scientists, providing nearly hard spheres to explore structure and dynamics. The poly(methyl methacrylate) latexes typically used are often refractive index matched by dispersing them in binary solvent mixtures, but this can lead to undesirable changes, such as particle charging or swelling. To avoid these shortcomings, we have synthesized refractive index matched colloids using polymerization-induced self-assembly (PISA) rather than as polymer latexes. The crucial difference is that these diblock copolymer nanoparticles consist of a single core-forming polymer in a single non-ionizable solvent. The diblock copolymer chosen was poly(stearyl methacrylate)-poly(2,2,2-trifluoroethyl methacrylate) (PSMA-PTFEMA), which self-assembles to form PTFEMA core spheres in n-alkanes. By monitoring scattered light intensity, n-tetradecane was found to be the optimal solvent for matching the refractive index of such nanoparticles. As expected for PISA syntheses, the diameter of the colloids can be controlled by varying the PTFEMA degree of polymerization. Concentrated dispersions were prepared, and the diffusion of the PSMA-PTFEMA nanoparticles as a function of volume fraction was measured. These diblock copolymer nanoparticles are a promising new system of transparent spheres for future colloidal studies.
Collapse
Affiliation(s)
- Gregory N Smith
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Matthew J Derry
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - James E Hallett
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1FD, UK
| | - Joseph R Lovett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | | | - Thomas J Neal
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Sylvain Prévost
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Steven P Armes
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| |
Collapse
|
10
|
Farrokhbin M, Stojimirović B, Galli M, Khajeh Aminian M, Hallez Y, Trefalt G. Surfactant mediated particle aggregation in nonpolar solvents. Phys Chem Chem Phys 2019; 21:18866-18876. [DOI: 10.1039/c9cp01985e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aggregation behavior of particles in nonpolar media is studied with time-resolved light scattering.
Collapse
Affiliation(s)
- Mojtaba Farrokhbin
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
| | - Biljana Stojimirović
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
| | - Marco Galli
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
| | | | - Yannick Hallez
- Laboratoire de Génie Chimique
- Université de Toulouse
- CNRS
- INPT
- UPS
| | - Gregor Trefalt
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
| |
Collapse
|
11
|
Schreuer C, Vandewiele S, Strubbe F, Neyts K, Beunis F. Electric field induced charging of colloidal particles in a nonpolar liquid. J Colloid Interface Sci 2018; 515:248-254. [DOI: 10.1016/j.jcis.2018.01.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 10/18/2022]
|