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Allegri G, Huskens J, Martinho RP, Lindhoud S. Distribution of polyelectrolytes and counterions upon polyelectrolyte complexation. J Colloid Interface Sci 2024; 672:654-663. [PMID: 38865879 DOI: 10.1016/j.jcis.2024.06.062] [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: 05/06/2024] [Revised: 06/06/2024] [Accepted: 06/06/2024] [Indexed: 06/14/2024]
Abstract
HYPOTHESIS Understanding polyelectrolyte complexation remains limited due to the absence of a systematic methodology for analyzing the distribution of components between the polyelectrolyte complex (PEC) and the dilute phases. EXPERIMENTS We developed a methodology based on NMR to quantify all components of solid-like PECs and their supernatant phases formed by mixing different ratios of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid)-sodium salt (PAA). This approach allowed for determining relative and absolute concentrations of polyelectrolytes in both phases by 1H NMR studies. Using 23Na and 35Cl NMR spectroscopy we measured the concentration of counterions in both phases. FINDINGS Regardless of the mixing ratio of the polyelectrolytes the PEC is charge-stoichiometric, and any excess polyelectrolytes to achieve charge stoichiometry remains in the supernatant phase. The majority of counterions were found in the supernatant phase, confirming counterion release being a major thermodynamic driving force for PEC formation. The counterion concentrations in the PEC phase were approximately twice as high as in the supernatant phase. The complete mass balance of PEC formation could be determined and translated into a molecular picture. It appears that PAH is fully charged, while PAA is more protonated, so less charged, and some 10% extrinsic PAH-Cl- pairs are present in the complex.
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Affiliation(s)
- Giulia Allegri
- Molecular Nanofabrication Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
| | - Jurriaan Huskens
- Molecular Nanofabrication Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
| | - Ricardo P Martinho
- Biomolecular Nanotechnology Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
| | - Saskia Lindhoud
- Molecular Nanofabrication Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
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2
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Tan J, Gjerde N, Del Giudice A, Knudsen KD, Galantini L, Du G, Schillén K, Sande SA, Nyström B. Interactions in Aqueous Mixtures of Cationic Hydroxyethyl Cellulose and Different Anionic Bile Salts. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:3732-3741. [PMID: 36791398 PMCID: PMC9983013 DOI: 10.1021/acs.jafc.3c00076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
It is known that the reduction of blood cholesterol can be accomplished through foods containing a large number of dietary fibers; this process is partially related to the binding of bile salt to fibers. To gain new insights into the interactions between dietary fibers and bile salts, this study investigates the interactions between cationic hydroxyethyl cellulose (catHEC) and sodium deoxycholate (NaDC) or sodium cholate (NaC), which have a similar structure. Turbidity measurements reveal strong interactions between catHEC and NaDC, and under some conditions, macroscopic phase separation occurs. In contrast, the interactions with NaC are weak. At a catHEC concentration of 2 wt %, incipient phase separation is approached at concentrations of NaC and NaDC of 32.5 and 19.3 mM, respectively. The rheological results show strong interactions and a prominent viscosification effect for the catHEC/NaDC system but only moderate interactions for the catHEC/NaC system. Both cryogenic transmission electron microscopy and small-angle X-ray scattering results display fundamental structural differences between the two systems, which may explain the stronger interactions in the presence of NaDC. The surmise is that the extended structures formed in the presence of NaDC can easily form connections and entanglements in the network.
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Affiliation(s)
- Julia
Jianwei Tan
- School
of Pharmacy, Department of Pharmaceutics, University of Oslo, P.O. Box 1068, Blindern, N-0316 Oslo, Norway
| | - Natalie Gjerde
- Department
of Chemistry, ‘‘Sapienza’’
University of Rome, P.O. Box 34, Roma 62, Piazzale A. Moro 5, I-00185 Roma, Italy
| | - Alessandra Del Giudice
- Department
of Chemistry, ‘‘Sapienza’’
University of Rome, P.O. Box 34, Roma 62, Piazzale A. Moro 5, I-00185 Roma, Italy
| | | | - Luciano Galantini
- Department
of Chemistry, ‘‘Sapienza’’
University of Rome, P.O. Box 34, Roma 62, Piazzale A. Moro 5, I-00185 Roma, Italy
| | - Guanqun Du
- Division
of Physical Chemistry, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Karin Schillén
- Division
of Physical Chemistry, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Sverre Arne Sande
- School
of Pharmacy, Department of Pharmaceutics, University of Oslo, P.O. Box 1068, Blindern, N-0316 Oslo, Norway
| | - Bo Nyström
- Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
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3
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Steinforth P, Gómez-Martínez M, Entgelmeier LM, García Mancheño O, Schönhoff M. Relevance of the Cation in Anion Binding of a Triazole Host: An Analysis by Electrophoretic Nuclear Magnetic Resonance. J Phys Chem B 2022; 126:10156-10163. [PMID: 36409921 PMCID: PMC9744096 DOI: 10.1021/acs.jpcb.2c05064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/24/2022] [Indexed: 11/22/2022]
Abstract
Triazole hosts allow cooperative binding of anions via hydrogen bonds, which makes them versatile systems for application in anion binding catalysis to be performed in organic solvents. The anion binding behavior of a tetratriazole host is systematically studied by employing a variety of salts, including chloride, acetate, and benzoate, as well as different cations. Classical nuclear magnetic resonance (1H NMR) titrations demonstrate a large influence of cation structures on the anion binding constant, which is attributed to poor dissociation of most salts in organic solvents and corrupts the results of classical titration techniques. We propose an approach employing electrophoretic NMR (eNMR), yielding drift velocities of each species in an electric field and thus allowing a distinction between charged and uncharged species. After the determination of the dissociation constants KD for the salts, electrophoretic mobilities are measured for all species in the host-salt system and are analyzed in a model which treats anion binding as a consecutive reaction to salt dissociation, yielding a corrected anion binding constant KA. Interestingly, dependence of KA on salt concentration occurs, which is attributed to cation aggregation with the anion-host complex. Finally, by the extrapolation to zero salt concentration, the true anion-host binding constant is obtained. Thus, the approach by eNMR allows a fully quantitative analysis of two factors that might impair classical anion binding studies, namely, an incomplete salt dissociation as well as the occurrence of larger aggregate species.
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Affiliation(s)
- Pascal Steinforth
- Institute
of Physical Chemistry, University of Münster, Corrensstrasse 28/30, 48149Münster, Germany
| | - Melania Gómez-Martínez
- Institute
of Organic Chemistry, University of Münster, Corrensstrasse 36, 48149Münster, Germany
| | | | - Olga García Mancheño
- Institute
of Organic Chemistry, University of Münster, Corrensstrasse 36, 48149Münster, Germany
| | - Monika Schönhoff
- Institute
of Physical Chemistry, University of Münster, Corrensstrasse 28/30, 48149Münster, Germany
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4
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Hill C, Abdullahi W, Crossman M, Griffiths PC. Using Polymer-Surfactant Charge Ratio to Control Synergistic Flocculation of Anionic Particulate Dispersions. Polymers (Basel) 2022; 14:polym14173504. [PMID: 36080579 PMCID: PMC9460132 DOI: 10.3390/polym14173504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
This study investigates the flocculation induced destabilization of particulate dispersions by oppositely charged polymer−surfactant complexes, with a particular focus on controlling interactions by modulating the charge ratio Z, (where Z = [+polymer]/[−surfactant]) via [−surfactant] at fixed Cpolymer. Cationic hydroxyethyl cellulose (cat-HEC) polymer-sodium dodecylsulfate (SDS) complexes were prepared with either excess polymer (Z > 1) or surfactant (Z < 1) charges. Anionic particulate dispersions (Ludox and polystyrene-butadiene Latex) were then exposed to the complexes, and solvent relaxation NMR was used to characterize the particle surfaces before and after exposure. In both particulate dispersions, flocculation induced destabilization was enhanced after exposure to cat-HEC-SDS complexes with Z > 1, leaving any excess particle surfaces uncoated after gentle centrifugation. However, complexes with Z < 1 showed no adsorption and destabilization in the Ludox dispersions and only slight destabilization in the Latex dispersions due to possible hydrophobic interactions. Substituting SDS for non-ionic surfactant (C12E6) showed no additional destabilization of the dispersions, but post-centrifugation relaxation rates indicated preferential adsorption of C12E6 onto the particle surfaces. Since the dominant forces are electrostatic, this study highlights the possibility of controlling the interactions between oppositely charged polymer−surfactant complexes and particle surfaces by modulating Z through [−surfactant].
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Affiliation(s)
- Christopher Hill
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK
| | - Wasiu Abdullahi
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK
| | - Martin Crossman
- Unilever Research, Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, UK
| | - Peter Charles Griffiths
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK
- Correspondence:
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Abdullahi W, Crossman M, Griffiths PC. Probing Selective Adsorption in Cationic-Polymer Induced Aggregation of Binary Anionic Particulate Dispersions Using Solvent Relaxation NMR. Polymers (Basel) 2022; 14:polym14091875. [PMID: 35567044 PMCID: PMC9104040 DOI: 10.3390/polym14091875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/22/2022] [Accepted: 05/01/2022] [Indexed: 11/16/2022] Open
Abstract
NMR solvent relaxation has been used to characterize the surfaces present in binary anionic particle dispersions, before and after exposure to a cationic polymer. In the polymer-free case, it is shown that the measured specific relaxation rate of the solvent is a population-weighted average of all surfaces present, enabling preferential adsorption to be explored. The addition of the oppositely charged polymer led to phase separation, which was accelerated by gentle centrifugation. The measured relaxation rates and the equilibrium particle concentrations indicate that the cationic hydroxyethylcellulose polymer (HEC LR) exhibited no significant preference for either latex or laponite in binary blends with silica, but a strong preference for TiO2. This study illustrates the versatility of solvent relaxation to probe surface area, surface type and dispersion composition in complex formulations.
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Affiliation(s)
- Wasiu Abdullahi
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK;
| | - Martin Crossman
- Unilever Research, Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, UK;
| | - Peter Charles Griffiths
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK;
- Correspondence: ; Tel.: +44-208-331-9549
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Del Sorbo GR, Clemens D, Schneck E, Hoffmann I. Stimuli-responsive polyelectrolyte surfactant complexes for the reversible control of solution viscosity. SOFT MATTER 2022; 18:2434-2440. [PMID: 35274665 DOI: 10.1039/d1sm01774h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Interactions of polyelectrolytes with oppositely charged surfactants can give rise to a large variety of self-assembled structures. Some of these systems cause a drastic increase in solution viscosity, which is related to the surfactant forming aggregates interconnecting several polyelectrolyte chains. For these aggregates to form, the surfactant needs to be sufficiently hydrophobic. Here, we present a system consisting of the anionic surfactant sodium monododecyl phosphate and the cationic cellulose-based polyelectrolyte JR 400. The hydrophobicity of the surfactant can be controlled by the solution's pH. At pH > 12, the surfactant headgroup bears two charges. As a consequence, the solution viscosity decreases drastically by up to two orders of magnitude, while it can be as high as 10 Pa s at lower pH. In this paper, we investigate the changes of the mesoscopic structure of the system which lead to such drastic changes in viscosity using small angle neutron scattering and neutron spin-echo spectroscopy. Such systems are potentially interesting as they allow for a modular design where stimuli responsiveness is introduced by relatively small amounts of surfactant reusing the same simple polyelectrolyte.
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Affiliation(s)
- Giuseppe Rosario Del Sorbo
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, D-14476 Potsdam, Germany
- Institut Max von Laue-Paul Langevin (ILL), 71 Avenue des Martyrs, CS 20156, F-38042 Grenoble Cedex 9, France.
| | - Daniel Clemens
- Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, D-14109, Berlin, Germany
| | - Emanuel Schneck
- Department of Physics, Technische Universität Darmstadt, Hochschulstraße 8, D-64289 Darmstadt, Germany.
| | - Ingo Hoffmann
- Institut Max von Laue-Paul Langevin (ILL), 71 Avenue des Martyrs, CS 20156, F-38042 Grenoble Cedex 9, France.
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7
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Lopez CG, Linders J, Mayer C, Richtering W. Diffusion and Viscosity of Unentangled Polyelectrolytes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01169] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Carlos G. Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Jürgen Linders
- Physical Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45117 Essen, Germany
| | - Christian Mayer
- Physical Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45117 Essen, Germany
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
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8
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Hill C, Abdullahi W, Dalgliesh R, Crossman M, Griffiths PC. Charge Modification as a Mechanism for Tunable Properties in Polymer-Surfactant Complexes. Polymers (Basel) 2021; 13:2800. [PMID: 34451340 PMCID: PMC8397960 DOI: 10.3390/polym13162800] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/02/2021] [Accepted: 08/17/2021] [Indexed: 11/17/2022] Open
Abstract
Oppositely charged polymer-surfactant complexes are frequently explored as a function of phase space defined by the charge ratio Z, (where Z = [+polymer]/[-surfactant]), commonly accessed through the surfactant concentration. Tuning the phase behaviour and related properties of these complexes is an important tool for optimising commercial formulations; hence, understanding the relationship between Z and bulk properties is pertinent. Here, within a homologous series of cationic hydroxyethyl cellulose (cat-HEC) polymers with minor perturbations in the degree of side chain charge modification, phase space is instead explored through [+polymer] at fixed Cpolymer. The nanostructures were characterised by small-angle neutron scattering (SANS) in D2O solutions and in combination with the oppositely charged surfactant sodium dodecylsulfate (h- or d-SDS). Scattering consistent with thin rods with an average radius of ∼7.7 Å and length of ∼85 Å was observed for all cat-HEC polymers and no significant interactions were shown between the neutral HEC polymer and SDS (CSDS < CMC). For the charge-modified polymers, interactions with SDS were evident and the radius of the formed complexes grew up to ∼15 Å with increasing Z. This study demonstrates a novel approach in which the Z phase space of oppositely charged polymer-surfactant complexes can be controlled at fixed concentrations.
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Affiliation(s)
- Christopher Hill
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK; (C.H.); (W.A.)
| | - Wasiu Abdullahi
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK; (C.H.); (W.A.)
| | - Robert Dalgliesh
- ISIS Neutron and Muon Source, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX, UK;
| | - Martin Crossman
- Unilever Research, Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, UK;
| | - Peter Charles Griffiths
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK; (C.H.); (W.A.)
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Patel L, Mansour O, Bryant H, Abdullahi W, Dalgliesh RM, Griffiths PC. Interaction of Low Molecular Weight Poly(diallyldimethylammonium chloride) and Sodium Dodecyl Sulfate in Low Surfactant-Polyelectrolyte Ratio, Salt-Free Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8815-8825. [PMID: 32668905 DOI: 10.1021/acs.langmuir.0c01149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Coacervation is widely used in formulations to induce a beneficial character to the formulation, but nonequilibrium effects are often manifest. Electrophoretic NMR (eNMR), pulsed-gradient spin-echo NMR (PGSE-NMR), and small-angle neutron scattering (SANS) have been used to quantify the interaction between low molecular cationic poly(diallyldimethylammonium chloride) (PDADMAC) and the anionic surfactant sodium dodecyl sulfate (SDS) in aqueous solution as a model for the precursor state to such nonequilibrium processes. The NMR data show that, within the low surfactant concentration one-phase region, an increasing surfactant concentration leads to a reduction in the charge on the polymer and a collapse of its solution conformation, attaining minimum values coincident with the macroscopic phase separation boundary. Interpretation of the scattering data reveals how the rodlike polymer changes over the same surfactant concentration window, with no discernible fingerprint of micellar type aggregates, but rather with the emergence of disklike and lamellar structures. At the highest surfactant concentration, the emergence of a weak Bragg peak in both the polymer and surfactant scattering suggests these precursor disk and lamellar structures evolve into paracrystalline stacks which ultimately phase separate. Addition of the nonionic surfactant hexa(ethylene glycol) monododecyl ether (C12E6) to the system seems to have little effect on the PDADMAC/SDS interaction as determined by NMR, merely displacing the observed behavior to lower SDS concentrations, commensurate with the total SDS present in the system. In other words, PDADMAC causes the disruption of the mixed SDS/C12E6 micelle, leading to SDS-rich PDADAMC/surfactant complexes coexisting with C12E6-rich micelles in solution.
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Affiliation(s)
- Leesa Patel
- Faculty of Engineering and Science, School of Science, University of Greenwich, Chatham, ME4 4TB, U.K
| | - Omar Mansour
- Faculty of Health and Life Sciences, Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester, LE1 9BH, U.K
| | - Hannah Bryant
- Faculty of Engineering and Science, School of Science, University of Greenwich, Chatham, ME4 4TB, U.K
| | - Wasiu Abdullahi
- Faculty of Engineering and Science, School of Science, University of Greenwich, Chatham, ME4 4TB, U.K
| | - Robert M Dalgliesh
- ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, U.K
| | - Peter C Griffiths
- Faculty of Engineering and Science, School of Science, University of Greenwich, Chatham, ME4 4TB, U.K
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Abdullahi W, Crossman M, Griffiths PC. Surfactant-Modulation of the Cationic-Polymer-Induced Aggregation of Anionic Particulate Dispersions. Polymers (Basel) 2020; 12:polym12020287. [PMID: 32024169 PMCID: PMC7077465 DOI: 10.3390/polym12020287] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 01/08/2020] [Indexed: 11/16/2022] Open
Abstract
Commodity formulations contain many chemically distinct components and their mutual interactions define the beneficial characteristics of the formulation. Mixing oppositely charged polymers and surfactants invariably induces macroscopic phase separation, to a degree dependent on the prevailing polymer and surface charge densities, and the interaction can be modulated by added ionic surfactants. Here, it is shown that a general universality exists between the charge present on a series of cationic-modified cellulose polymers—the charge being controlled either by the degree of cationic modification of the polymer itself or through the subsequent level of anionic surfactant binding—and its capacity to remove anionic colloidal material from solution, be that silica particles or polystyrene-butadiene lattices. Particulate material not removed from solution bears no adsorbed polymer, i.e., the particle surface is bare. Addition of nonionic surfactant does not negate this universality, implying that the nonionic surfactant is largely a spectator molecule or structure (micelle) in these systems, and that the dominant force is an electrostatic one.
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Affiliation(s)
- Wasiu Abdullahi
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK;
| | - Martin Crossman
- Unilever Research, Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, UK;
| | - Peter Charles Griffiths
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK;
- Correspondence: ; Tel.: +44-208-331-9549
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