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Gomes PA, d'Espinose de Lacaillerie JB, Lartiges B, Maliet M, Molinier V, Passade-Boupat N, Sanson N. Microalgae as Soft Permeable Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14044-14052. [PMID: 36343201 DOI: 10.1021/acs.langmuir.2c01735] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The colloidal stability of non-motile algal cells in water drives their distribution in space. An accurate description of the interfacial properties of microalgae is therefore critical to understand how microalgae concentrations can change in their biotope or during harvesting processes. Here, we probe the surface charges of three unicellular algae─Chlorella vulgaris, Nannochloropsis oculata, and Tetraselmis suecica─through their electrophoretic mobility. Ohshima's soft particle theory describes the electrokinetic properties of particles covered by a permeable polyelectrolyte layer, a usual case for biological particles. The results appear to fit the predictions of Ohshima's theory, proving that all three microalgae behave electrokinetically as soft particles. This allowed us to estimate two characteristic parameters of the polyelectrolyte external layer of microalgae: the volume charge density and the hydrodynamic penetration length. Results were compared with transmission electron microscopy observations of the algal cells' surfaces, and in particular of their extracellular polymeric layer, which was identified with the permeable shell evidenced by electrophoretic measurements. Noticeably, the algal surface potentials estimated from electrophoretic mobility using the soft particle theory are less negative than the apparent zeta potentials. This finding indicates that electrostatics are expected to play a minor role in phenomena of environmental and industrial importance, such as microalgae aggregation or adhesion.
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Affiliation(s)
- Paula Araujo Gomes
- Soft Matter Sciences and Engineering Laboratory, ESPCI Paris, Université PSL, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7615, 10 Rue Vauquelin, F-75005Paris, France
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI Paris, 10 Rue Vauquelin, F-75231Paris, France
- TotalEnergies OneTech, Pôle d'Etudes et Recherche de Lacq, BP 47, 64170Lacq, France
| | - Jean-Baptiste d'Espinose de Lacaillerie
- Soft Matter Sciences and Engineering Laboratory, ESPCI Paris, Université PSL, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7615, 10 Rue Vauquelin, F-75005Paris, France
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI Paris, 10 Rue Vauquelin, F-75231Paris, France
| | - Bruno Lartiges
- Géosciences Environnement Toulouse (GET), Université de Toulouse 3 (Paul Sabatier), 14 Avenue Edouard Belin, 31400Toulouse, France
| | - Martin Maliet
- Soft Matter Sciences and Engineering Laboratory, ESPCI Paris, Université PSL, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7615, 10 Rue Vauquelin, F-75005Paris, France
| | - Valérie Molinier
- TotalEnergies OneTech, Pôle d'Etudes et Recherche de Lacq, BP 47, 64170Lacq, France
- Laboratoire Physico-Chimie des Interfaces Complexes, Bâtiment CHEMSTARTUP, Route Départemental 817, 64170Lacq, France
| | - Nicolas Passade-Boupat
- TotalEnergies OneTech, Pôle d'Etudes et Recherche de Lacq, BP 47, 64170Lacq, France
- Laboratoire Physico-Chimie des Interfaces Complexes, Bâtiment CHEMSTARTUP, Route Départemental 817, 64170Lacq, France
| | - Nicolas Sanson
- Soft Matter Sciences and Engineering Laboratory, ESPCI Paris, Université PSL, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7615, 10 Rue Vauquelin, F-75005Paris, France
- Laboratoire Physico-Chimie des Interfaces Complexes, ESPCI Paris, 10 Rue Vauquelin, F-75231Paris, France
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2
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Alvarez L, Fernandez-Rodriguez MA, Alegria A, Arrese-Igor S, Zhao K, Kröger M, Isa L. Reconfigurable artificial microswimmers with internal feedback. Nat Commun 2021; 12:4762. [PMID: 34362934 PMCID: PMC8346629 DOI: 10.1038/s41467-021-25108-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 07/17/2021] [Indexed: 11/09/2022] Open
Abstract
Self-propelling microparticles are often proposed as synthetic models for biological microswimmers, yet they lack the internally regulated adaptation of their biological counterparts. Conversely, adaptation can be encoded in larger-scale soft-robotic devices but remains elusive to transfer to the colloidal scale. Here, we create responsive microswimmers, powered by electro-hydrodynamic flows, which can adapt their motility via internal reconfiguration. Using sequential capillary assembly, we fabricate deterministic colloidal clusters comprising soft thermo-responsive microgels and light-absorbing particles. Light absorption induces preferential local heating and triggers the volume phase transition of the microgels, leading to an adaptation of the clusters' motility, which is orthogonal to their propulsion scheme. We rationalize this response via the coupling between self-propulsion and variations of particle shape and dielectric properties upon heating. Harnessing such coupling allows for strategies to achieve local dynamical control with simple illumination patterns, revealing exciting opportunities for developing tactic active materials.
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Affiliation(s)
- L Alvarez
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zurich, Zurich, Switzerland.
| | - M A Fernandez-Rodriguez
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zurich, Zurich, Switzerland
- Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, Granada, Spain
| | - A Alegria
- Centro de Física de Materiales (CSIC-UPV/EHU), Materials Physics Center, San Sebastián, Spain
| | - S Arrese-Igor
- Centro de Física de Materiales (CSIC-UPV/EHU), Materials Physics Center, San Sebastián, Spain
| | - K Zhao
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - M Kröger
- Polymer Physics, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zurich, Zurich, Switzerland.
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3
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Saha P, Ganguly R, Li X, Das R, Singha NK, Pich A. Zwitterionic Nanogels and Microgels: An Overview on Their Synthesis and Applications. Macromol Rapid Commun 2021; 42:e2100112. [PMID: 34021658 DOI: 10.1002/marc.202100112] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/24/2021] [Indexed: 12/12/2022]
Abstract
Zwitterionic polymers by virtue of their unique chemical and physical attributes have attracted researchers in recent years. The simultaneous presence of positive and negative charges in the same repeat unit renders them of various interesting properties such as superhydrophilicity, which has significantly broadened their scope for being used in different applications. Among polyzwitterions of different architectures, micro- and/or nano-gels have started receiving attention only until recently. These 3D cross-linked colloidal structures show peculiar characteristics in context to their solution properties, which are attributable either to the comonomers present or the presence of different electrolytes and biological specimens. In this review, a concise yet detailed account is provided of the different synthetic techniques and application domains of zwitterion-based micro- and/or nanogels that have been explored in recent years. Here, the focus is kept solely on the "polybetaines," which have garnered maximum research interest and remain the extensively studied polyzwitterions in literature. While their vast application potential in the biomedical sector is being detailed here, some other areas of scope such as using them as microreactors for the synthesis of metal nanoparticles or making smart membranes for water-treatment are discussed in this minireview as well.
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Affiliation(s)
- Pabitra Saha
- DWI - Leibniz-Institute for Interactive Materials, 52074, Aachen, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, 52062, Aachen, Germany
| | - Ritabrata Ganguly
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, Kharagpur, 721302, India
| | - Xin Li
- DWI - Leibniz-Institute for Interactive Materials, 52074, Aachen, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, 52062, Aachen, Germany
| | - Rohan Das
- Luxembourg Institute of Science and Technology (LIST), Avenue des Hauts-Fourneaux, Esch-sur-Alzette, 4362, Luxembourg
| | - Nikhil K Singha
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, Kharagpur, 721302, India
| | - Andrij Pich
- DWI - Leibniz-Institute for Interactive Materials, 52074, Aachen, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, 52062, Aachen, Germany.,Aachen Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Geleen, 6167, The Netherlands
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4
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Kawaguchi H. On Going to a New Era of Microgel Exhibiting Volume Phase Transition. Gels 2020; 6:gels6030026. [PMID: 32824458 PMCID: PMC7559898 DOI: 10.3390/gels6030026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/03/2020] [Accepted: 08/10/2020] [Indexed: 12/14/2022] Open
Abstract
The discovery of phenomena of volume phase transition has had a great impact not only on bulk gels but also on the world of microgels. In particular, research on poly(N-isopropylacrylamide) (PNIPAM) microgels, whose transition temperature is close to body temperature, has made remarkable progress in almost 35 years. This review presents some breakthrough findings in microgels that exhibit volume phase transitions and outlines recent works on the synthesis, structural analysis, and research direction of microgels.
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Affiliation(s)
- Haruma Kawaguchi
- Faculty of Science and Technology, Keio University, Hiyoshi, Yokohama 241-0814, Japan
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5
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Varga I, Kardos A, Borsos A, Gilányi T. Effect of internal charge distribution on the electrophoretic mobility of poly(N-isopropylacrylamide) based core-shell microgel particles. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.111979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Electrophoresis of composite soft particles with differentiated core and shell permeabilities to ions and fluid flow. J Colloid Interface Sci 2019; 558:280-290. [PMID: 31593861 DOI: 10.1016/j.jcis.2019.09.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/27/2019] [Accepted: 09/28/2019] [Indexed: 11/20/2022]
Abstract
Within the framework of analytical theories for soft surface electrophoresis, soft particles are classically defined by a hard impermeable core of given surface charge density surrounded by a polyelectrolyte shell layer permeable to both electroosmotic flow and ions from background electrolyte. This definition excludes practical core-shell particles, e.g. dendrimers, viruses or multi-layered polymeric particles, defined by a polyelectrolytic core where structural charges are distributed and where counter-ions concentration and electroosmotic flow velocity can be significant. Whereas a number of important approximate expressions has been derived for the electrophoretic mobility of hard and soft particles, none of them is applicable to such generic composite core-shell particles with differentiated ions- and fluid flow-permeabilities of their core and shell components. In this work, we elaborate an original closed-form electrophoretic mobility expression for this generic composite particle type within the Debye-Hückel electrostatic framework and thin double layer approximation. The expression explicitly involves the screening Debye layer thickness and the Brinkman core and shell hydrodynamic length scales, which favors so-far missing analysis of the respective core and shell contributions to overall particle mobility. Limits of this expression successfully reproduce results from Ohshima's electrophoresis theory solely applicable to soft particles with or without hard core.
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7
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Denton AR, Alziyadi MO. Osmotic pressure of permeable ionic microgels: Poisson-Boltzmann theory and exact statistical mechanical relations in the cell model. J Chem Phys 2019; 151:074903. [DOI: 10.1063/1.5091115] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Alan R. Denton
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA
| | - Mohammed O. Alziyadi
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA
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8
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Keskin D, Mergel O, van der Mei HC, Busscher HJ, van Rijn P. Inhibiting Bacterial Adhesion by Mechanically Modulated Microgel Coatings. Biomacromolecules 2019; 20:243-253. [PMID: 30512925 PMCID: PMC6335679 DOI: 10.1021/acs.biomac.8b01378] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/02/2018] [Indexed: 02/06/2023]
Abstract
Bacterial infection is a severe problem especially when associated with biomedical applications. This study effectively demonstrates that poly- N-isopropylmethacrylamide based microgel coatings prevent bacterial adhesion. The coating preparation via a spraying approach proved to be simple and both cost and time efficient creating a homogeneous dense microgel monolayer. In particular, the influence of cross-linking density, microgel size, and coating thickness was investigated on the initial bacterial adhesion. Adhesion of Staphylococcus aureus ATCC 12600 was imaged using a parallel plate flow chamber setup, which gave insights in the number of the total bacteria adhering per unit area onto the surface and the initial bacterial deposition rates. All microgel coatings successfully yielded more than 98% reduction in bacterial adhesion. Bacterial adhesion depends both on the cross-linking density/stiffness of the microgels and on the thickness of the microgel coating. Bacterial adhesion decreased when a lower cross-linking density was used at equal coating thickness and at equal cross-linking density with a thicker microgel coating. The highest reduction in the number of bacterial adhesion was achieved with the microgel that produced the thickest coating ( h = 602 nm) and had the lowest cross-linking density. The results provided in this paper indicate that microgel coatings serve as an interesting and easy applicable approach and that it can be fine-tuned by manipulating the microgel layer thickness and stiffness.
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Affiliation(s)
- Damla Keskin
- University
of Groningen, University Medical Center Groningen, Department of Biomedical
Engineering (FB40), W.J. Kolff Institute
for Biomedical Engineering and Materials Science (FB41), Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Olga Mergel
- University
of Groningen, University Medical Center Groningen, Department of Biomedical
Engineering (FB40), W.J. Kolff Institute
for Biomedical Engineering and Materials Science (FB41), Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Henny C. van der Mei
- University
of Groningen, University Medical Center Groningen, Department of Biomedical
Engineering (FB40), W.J. Kolff Institute
for Biomedical Engineering and Materials Science (FB41), Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Henk J. Busscher
- University
of Groningen, University Medical Center Groningen, Department of Biomedical
Engineering (FB40), W.J. Kolff Institute
for Biomedical Engineering and Materials Science (FB41), Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Patrick van Rijn
- University
of Groningen, University Medical Center Groningen, Department of Biomedical
Engineering (FB40), W.J. Kolff Institute
for Biomedical Engineering and Materials Science (FB41), Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
- University of
Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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9
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Weyer TJ, Denton AR. Concentration-dependent swelling and structure of ionic microgels: simulation and theory of a coarse-grained model. SOFT MATTER 2018; 14:4530-4540. [PMID: 29796467 DOI: 10.1039/c8sm00799c] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We study swelling and structural properties of ionic microgel suspensions within a comprehensive coarse-grained model that combines the polymeric and colloidal natures of microgels as permeable, compressible, charged spheres governed by effective interparticle interactions. The model synthesizes the Flory-Rehner theory of cross-linked polymer gels, the Hertz continuum theory of effective elastic interactions, and a theory of density-dependent effective electrostatic interactions. Implementing the model using Monte Carlo simulation and thermodynamic perturbation theory, we compute equilibrium particle size distributions, swelling ratios, volume fractions, net valences, radial distribution functions, and static structure factors as functions of concentration. Trial Monte Carlo moves comprising particle displacements and size variations are accepted or rejected based on the total change in elastic and electrostatic energies. The theory combines first-order thermodynamic perturbation and variational free energy approximations. For illustrative system parameters, theory and simulation agree closely at concentrations ranging from dilute to beyond particle overlap. With increasing concentration, as microgels deswell, we predict a decrease in the net valence and an unusual saturation of pair correlations. Comparison with experimental data for deionized, aqueous suspensions of PNIPAM particles demonstrates the capacity of the coarse-grained model to predict and interpret measured swelling behavior.
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Affiliation(s)
- Tyler J Weyer
- Department of Physics, North Dakota State University, Fargo, ND 58108-6050, USA.
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10
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Urich M, Denton AR. Swelling, structure, and phase stability of compressible microgels. SOFT MATTER 2016; 12:9086-9094. [PMID: 27774556 DOI: 10.1039/c6sm02056a] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Microgels are soft colloidal particles that, when dispersed in a solvent, swell and deswell in response to changes in environmental conditions, such as temperature, concentration, and pH. Using Monte Carlo simulation, we model bulk suspensions of microgels that interact via Hertzian elastic interparticle forces and can expand or contract via trial moves that allow particles to change size in accordance with the Flory-Rehner free energy of cross-linked polymer gels. We monitor the influence of particle compressibility, size fluctuations, and concentration on bulk structural and thermal properties by computing particle swelling ratios, radial distribution functions, static structure factors, osmotic pressures, and freezing densities. For microgels in the nanoscale size range, particle compressibility and associated size fluctuations suppress crystallization, shifting the freezing transition to a higher density than for the hard-sphere fluid. As densities increase beyond close packing, microgels progressively deswell, while their intrinsic size distribution grows increasingly polydisperse.
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Affiliation(s)
- Matthew Urich
- Department of Physics, North Dakota State University, Fargo, ND 58108-6050, USA.
| | - Alan R Denton
- Department of Physics, North Dakota State University, Fargo, ND 58108-6050, USA.
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11
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Affiliation(s)
- Alan R. Denton
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA
| | - Qiyun Tang
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA
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12
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Späth A, Graf-Zeiler BA, Paradossi G, Ghugare S, Tzvetkov G, Fink RH. Quantitative X-ray microscopic analysis of individual thermoresponsive microgel particles in aqueous solution. RSC Adv 2016. [DOI: 10.1039/c6ra20142c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The temperature dependent phase transition of individual thermoresponsive microgel particles in aqueous solution has been studied by high resolution soft X-ray transmission microscopy (STXM).
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Affiliation(s)
- Andreas Späth
- Physikalische Chemie II
- ICMM
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- 91058 Erlangen
- Germany
| | - Birgit A. Graf-Zeiler
- Physikalische Chemie II
- ICMM
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- 91058 Erlangen
- Germany
| | - Gaio Paradossi
- Dipartimento di Scienze e Tecnologie Chimiche
- Università di Roma Tor Vergata
- 00133 Roma
- Italy
| | - Shivkumar Ghugare
- Dipartimento di Scienze e Tecnologie Chimiche
- Università di Roma Tor Vergata
- 00133 Roma
- Italy
| | - George Tzvetkov
- Department of Inorganic Chemistry
- Faculty of Chemistry
- University of Sofia
- 1164 Sofia
- Bulgaria
| | - Rainer H. Fink
- Physikalische Chemie II
- ICMM
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- 91058 Erlangen
- Germany
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13
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Li G, Yang M, Ma P, Zhang G. Nanoparticles change drop breakup mechanism to obtain icecream-like microparticles in inverse suspension polymerization. RSC Adv 2016. [DOI: 10.1039/c5ra22376h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nanoparticle modify particle shaped in suspension polymerization by changing drop breakup. (a) 0.4% initiator, (b) 0.05% initiator.
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Affiliation(s)
- Guanghui Li
- Department of Petroleum Engineering
- Yanshan University
- Qinhuangdao
- China
| | - Manping Yang
- Department of Petroleum Engineering
- Yanshan University
- Qinhuangdao
- China
| | - Pinghua Ma
- Department of Petroleum Engineering
- Yanshan University
- Qinhuangdao
- China
| | - Guicai Zhang
- College of Petroleum Engineering
- China University of Petroleum (East China)
- Qingdao
- China
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14
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Zhou J, Li D, Su C, Wen H, Du Q, Liang D. Peptides containing blocks of different charge densities facilitate cell uptake of oligonucleotides. Phys Chem Chem Phys 2015; 17:8653-9. [PMID: 25735601 DOI: 10.1039/c4cp05988c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polyelectrolyte complexes (PECs) are of great importance in drug delivery and gene therapy. The density and the distribution of the charges are key parameters of a polyelectrolyte, determining the structure of the complex and the kinetics of the complexation. Using peptides of precisely-controlled charge density as model molecules, we showed that the presence of weakly-charged peptides, (KGGG)5 or (KGKG)5, did not affect the complexation of highly-charged peptides (KKKK)5 with 21 bp oligonucleotides. However, peptide containing blocks of different charge densities, such as (KKKK)5-b-(KGGG)5 or (KKKK)5-b-(KGKG)5, exhibited superior performance during complexation. With a relatively uniform small size, the complex was also stable in serum. More importantly, the cellular uptake of the complex was greatly enhanced by a ratio of 40-60%, compared to that of the complex formed by uniformly-charged peptides. We attributed the improvement to the structure of the complex, in which the highly-charged blocks form the core with the oligonucleotide whilst the weakly-charged blocks dangle outside, preventing the complexes from further aggregation.
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Affiliation(s)
- Jihan Zhou
- Beijing National Laboratory for Molecular Sciences and the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100871, China.
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15
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Hedrick MM, Chung JK, Denton AR. Structure and osmotic pressure of ionic microgel dispersions. J Chem Phys 2015; 142:034904. [DOI: 10.1063/1.4905574] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Mary M. Hedrick
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, USA
| | - Jun Kyung Chung
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA
| | - Alan R. Denton
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA
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16
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Kokufuta E, Sato S, Kokufuta MK. Electrophoretic behavior of microgel-immobilized polyions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15442-15449. [PMID: 24256424 DOI: 10.1021/la403597u] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Electrophoretic behavior was studied for N-isopropylacrylamide (NIPA) microgels, into which different amounts of poly(acrylic acid) (PAAc) were physically entrapped. Copolymer microgels of NIPA with acrylic acid (AAc) were also studied as a control. Electrophoretic mobility was measured in 0.1 M NaCl solution at 25 °C as a function of pH, using an electrophoretic light scattering technique. The mobility of the copolymer microgel whose COOH groups are fully ionized agreed with that of PAAc when its ionization degree (α(n)) is close to the mole fraction (f(AAc)) of the AAc unit in the copolymer gel. There was good agreement between the mobility values of the copolymer microgel and the linear NIPA/AAc copolymer when their AAc contents are very close to each other. However, the mobility of the microgel with immobilized PAAc was higher than that of the copolymer microgel, even when there was no difference in the AAc content for both microgels. Moreover, the immobilized PAAc showed a higher mobility than the free PAAc when its α(n) is equal to f(AAc) in the immobilized system. No correlation was observed between the mobility and the hydrodynamic radius. These results were discussed in terms of the free draining model (FDM) for the electrophoresis of polyelectrolytes. It became apparent that the mobility difference depending upon whether (i) the PAAc ions are in the cage of the NIPA network or (ii) the AAc units are copolymerized with the network chain is due to the structural difference of the segments considered in the FDM.
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Affiliation(s)
- Etsuo Kokufuta
- Faculty of Life and Environmental Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8572, Japan
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17
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Thermoresponsive poly-(N-isopropylmethacrylamide) microgels: Tailoring particle size by interfacial tension control. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.08.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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18
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19
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Motion of microgels in electric fields. Adv Colloid Interface Sci 2009; 147-148:178-85. [PMID: 18790469 DOI: 10.1016/j.cis.2008.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 06/30/2008] [Accepted: 07/08/2008] [Indexed: 11/23/2022]
Abstract
We review existing experimental results on the motion of microgels in the presence of electric fields and find that there can be striking differences depending on whether the polymer network comprising the microgel is neutral or charged: While for neutral microgels, the electrophoretic mobility, micro, typically decreases as the particle swells, in the case of ionic microgels, micro typically increases with particle swelling. We explain this difference in behavior by recurring to electro-osmotic fluid flows inside the particles, which are relevant in the presence of electric fields when the polymer network is ionized; these flows render the particles permeable to the solvent qualitatively changing the way to think about their electrophoretic behavior. We show that this interpretation is consistent with calculations of the drag force experienced by a permeable object as it moves inside a liquid and with recent theoretical models for the electrophoresis of soft particles. The analysis emphasizes that the electrophoresis of neutral microgels can be qualitatively treated as that of charged hard spheres, irrespective on whether the particles are swollen or de-swollen. By contrast, ionic microgels behave like free-draining polyelectrolytes in the presence of electric fields.
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Brugger B, Rosen BA, Richtering W. Microgels as stimuli-responsive stabilizers for emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:12202-12208. [PMID: 18839977 DOI: 10.1021/la8015854] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Temperature- and pH-sensitive microgels from cross-linked poly(N-isopropylacrylamide)-co-methacrylic acid are utilized for emulsion stabilization. The pH- and temperature-dependent stability of the prepared emulsion was characterized. Stable emulsions are obtained at high pH and room temperature. Emulsions with polar oils, like 1-octanol, can be broken by either addition of acid or an increase of temperature, whereas emulsions with unpolar oils do not break upon these stimuli. However, complete phase separation, independent of oil polarity, can be achieved by successive acid addition and heating. This procedure also offers a way to recover and recycle the microgel from the sample. Interfacial dilatational rheology data correlate with the stimuli sensitivity of the emulsion, and a strong dependence of the interfacial elastic and loss moduli on pH and temperature was found. The influence of the preparation method on the type of emulsion is demonstrated. The mean droplet size of the emulsions is characterized by means of flow particle image analysis. The type of emulsion [water in oil (w/o) or oil in water (o/w)] depends on the preparation technique as well as on the microgel content. Emulsification with high shear rates allows preparation of both w/o and o/w emulsions, whereas with low shear rates o/w emulsions are the preferred type. The emulsions are stable at high pH and low temperature, but instable at low pH and high temperature. Therefore, we conclude that poly(N-isopropylacrylamide)-co-methacrylic acid microgels can be used as stimuli-sensitive stabilizers for emulsions. This offers a new and unique way to control emulsion stability.
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Affiliation(s)
- Bastian Brugger
- Institute of Physical Chemistry, RWTH Aachen University, Aachen, Germany
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Brugger B, Richtering W. Emulsions stabilized by stimuli-sensitive poly(N-isopropylacrylamide)-co-methacrylic acid polymers: microgels versus low molecular weight polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7769-7777. [PMID: 18613705 DOI: 10.1021/la800522h] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Responsive polymer microgels can be employed for the preparation of stimuli-sensitive emulsions. The microgels used in this study are based on cross-linked copolymers including N-isopropylacrylamide and methacrylic acid. We conducted the synthesis under acidic and basic conditions to investigate the effect of changes of comonomer solubility on the microgel's composition and ability to stabilize emulsions. The synthesis product was partially divided into two fractions by centrifugation. Raw product, collected supernatant, and purified microgel were characterized by means of light scattering, titration, as well as electrophoretic mobility. The ability of the three components to act as stabilizers was investigated by preparing the octanol/water emulsions and looking at their response to pH and temperature changes. The interfacial activity of the three components was characterized by means of the pendent drop technique. Furthermore, we investigated the response of the interface to dilatational stress using a pendant drop tensiometer equipped with an oscillating drop module. The results demonstrate that the pH during synthesis has a significant impact on the composition and thus the properties of the microgel and its ability to be utilized as a stimuli responsive stabilizer for emulsions. We conclude that microgels can be used as stimuli-sensitive stabilizers for emulsions, if the charges are incorporated in the microgel itself.
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Affiliation(s)
- Bastian Brugger
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056 Aachen, Germany
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22
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Bradley M, Vincent B. Poly(vinylpyridine) core/poly(N-isopropylacrylamide) shell microgel particles: their characterization and the uptake and release of an anionic surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:2421-5. [PMID: 18294014 DOI: 10.1021/la703327v] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The use of microgel particles for controlled uptake and release of active species has great potential. The compatibility of microgel particles with their environment and the functionality of the particles can be achieved by modification of the core microgel through the addition of a shell. In this work, core-shell microgel particles, with a pH-responsive core (polyvinylpyridine) and a temperature-responsive shell (poly-N-isopropylacrylamide), have been prepared and characterized. The uptake and release of an anionic surfactant from the microgels has been investigated as a function of solution pH and temperature. The results indicate that electrostatic attraction between the anionic surfactant and the cationically charged core of the microgel particles is the dominant mechanism for absorption of the surfactant into the core-shell microgel particles.
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Affiliation(s)
- Melanie Bradley
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom.
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Tan BH, Tam KC. Review on the dynamics and micro-structure of pH-responsive nano-colloidal systems. Adv Colloid Interface Sci 2008; 136:25-44. [PMID: 17707760 DOI: 10.1016/j.cis.2007.07.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Revised: 07/05/2007] [Accepted: 07/05/2007] [Indexed: 11/30/2022]
Abstract
This review presents an overview on the research on pH-responsive microgel particles in the last 10 years. Microgels are cross-linked latex particles that are swollen in a good solvent. Significant quantitative studies have been conducted to investigate the swelling behavior (microscopic) and rheological (macroscopic) properties of the pH-responsive microgel particles as a function of neutralization degree, ionic strength, and cross-linked density. Mono-dispersed, alkali-swellable microgels containing carboxylic acid lattices, whose properties display extreme pH sensitivity in water is considered in detail in terms of swelling behavior and rheological properties. Their stability in solution and ability to undergo reversible volume phase transitions in response to pH makes them ideal model systems for the development of a semi-empirical as well as theoretical approach for predicting the viscosity of dilute and concentrated hard and soft sphere systems. The review concludes with a discussion of some recent applications of pH-responsive microgel particles.
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Affiliation(s)
- Beng H Tan
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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24
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Sierra-Martín B, Romero-Cano MS, Fernández-Nieves A, Fernández-Barbero A. Thermal control over the electrophoresis of soft colloidal particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:3586-90. [PMID: 16584230 DOI: 10.1021/la053434m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We study the electrophoresis of surface-charged thermosensitive microgel particles based on poly-N-isopropylacrylamide (PNIPAM); these deswell with increasing temperature T. Our results show that the electrophoretic mobility mu is affected by the temperature-induced volume phase transition. It increases with increasing temperature, as a result of the charge density increase induced by particle deswelling. Temperature thus allows control of mu, in contrast to the more conventional charged hard spheres for which mu is T independent. Salt also affects the mu behavior and gives rise to rich phenomenology, sharing common characteristics with charged hard spheres and polyelectrolyte-coated colloids depending on whether the microgels are swollen or deswollen. We interpret the effects of salt concentration n by considering that particle charges are located in an external shell, as confirmed by titrations, and that it is this shell-salt-induced compression that affects the resulting mu behavior.
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Affiliation(s)
- B Sierra-Martín
- Group of Complex Fluids Physics, Department of Applied Physics, University of Almería, 04120 Almería, Spain
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Duval JFL, Ohshima H. Electrophoresis of diffuse soft particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:3533-46. [PMID: 16584225 DOI: 10.1021/la0528293] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
A theory is presented for the electrophoresis of diffuse soft particles in a steady dc electric field. The particles investigated consist of an uncharged impenetrable core and a charged diffuse polyelectrolytic shell, which is to some extent permeable to ions and solvent molecules. The diffuse character of the shell is defined by a gradual distribution of the density of polymer segments in the interspatial region separating the core from the bulk electrolyte solution. The hydrodynamic impact of the polymer chains on the electrophoretic motion of the particle is accounted for by a distribution of Stokes resistance centers. The numerical treatment of the electrostatics includes the possibility of partial dissociation of the hydrodynamically immobile ionogenic groups distributed throughout the shell as well as specific interaction between those sites with ions from the background electrolyte other than charge-determining ions. Electrophoretic mobilities are computed on the basis of an original numerical scheme allowing rigorous evaluation of the governing transport and electrostatic equations derived following the strategy reported by Ohshima, albeit within the restricted context of a discontinuous chain distribution. Attention is particularly paid to the influence of the type of distribution adopted on the electrophoretic mobility of the particle as a function of its size, charge, degree of permeability, and solution composition. The results are systematically compared with those obtained with a discontinuous representation of the interface. The theory constitutes a basis for interpreting electrophoretic mobilities of heterogeneous systems such as environmental or biological colloids or swollen/deswollen microgel particles.
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Affiliation(s)
- Jérôme F L Duval
- Department of Physical Chemistry and Colloid Science, Wageningen Universiteit, Dreijenplein 6, 6703 HB Wageningen, The Netherlands.
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Sierra-Martín B, Romero-Cano MS, Fernández-Barbero A. Anomalous electrophoretic mobility of microgel particles in buffer solutions. Colloid Polym Sci 2006. [DOI: 10.1007/s00396-006-1481-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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