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Usuelli M, Ruzzi V, Buzzaccaro S, Nyström G, Piazza R, Mezzenga R. Unraveling gelation kinetics, arrested dynamics and relaxation phenomena in filamentous colloids by photon correlation imaging. SOFT MATTER 2022; 18:5632-5644. [PMID: 35861104 DOI: 10.1039/d1sm01578h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The fundamental understanding of the gelation kinetics, stress relaxation and temporal evolution in colloidal filamentous gels is central to many aspects of soft and biological matter, yet a complete description of the inherent complex dynamics of these systems is still missing. By means of photon correlation imaging (PCI), we studied the gelation of amyloid fibril solutions, chosen as a model filamentous colloid with immediate significance to biology and nanotechnology, upon passage of ions through a semi-permeable membrane. We observed a linear-in-time evolution of the gelation front and rich rearrangement dynamics of the gels, the magnitude and the spatial propagation of which depend on how effectively electrostatic interactions are screened by different ionic strengths. Our analysis confirms the pivotal role of salt concentration in tuning the properties of amyloid gels, and suggests potential routes for explaining the physical mechanisms behind the linear advance of the salt ions.
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Affiliation(s)
- Mattia Usuelli
- ETH Zürich, Department of Health Sciences and Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland.
| | - Vincenzo Ruzzi
- Department of Chemistry, Materials Science, and Chemical Engineering (CMIC), Politecnico di Milano, Edificio 6, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
| | - Stefano Buzzaccaro
- Department of Chemistry, Materials Science, and Chemical Engineering (CMIC), Politecnico di Milano, Edificio 6, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
| | - Gustav Nyström
- ETH Zürich, Department of Health Sciences and Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland.
- EMPA, Laboratory for Cellulose & Wood Materials, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Roberto Piazza
- Department of Chemistry, Materials Science, and Chemical Engineering (CMIC), Politecnico di Milano, Edificio 6, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
| | - Raffaele Mezzenga
- ETH Zürich, Department of Health Sciences and Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland.
- ETH Zürich, Department of Materials, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
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Carrique F, Ruiz-Reina E, Arroyo FJ, Jiménez ML, Ahualli S, Delgado AV. Electrokinetic and dielectric response of a concentrated salt-free colloid: Different approaches to counterion finite-size effects. Phys Rev E 2022; 105:064604. [PMID: 35854619 DOI: 10.1103/physreve.105.064604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/25/2022] [Indexed: 06/15/2023]
Abstract
In the present work, a general model is developed for the electrokinetics and dielectric response of a concentrated salt-free colloid that takes into account the finite size of the counterions released by the particles to the solution. The effects associated with the counterion finite size have been addressed using a hard-sphere model approach elaborated by Carnahan and Starling [N. F. Carnahan and K. E. Starling, Equation of state for nonattracting rigid spheres, J. Chem. Phys. 51, 635 (1969)0021-960610.1063/1.1672048]. A more simple description of the finite size of the counterions based on that by Bikerman has also been considered for comparison. The studies carried out in this work include predictions on the effect of the finite counterion size on the equilibrium properties of the colloid and its electrokinetic and dielectric response when it is subjected to constant or alternating electric fields. The results show how important the counterion finite-size effects are for most of the electrokinetic and dielectric properties of highly charged and concentrated colloids, mainly for the static and dynamic electrophoretic mobilities. Furthermore, new insights are provided on the counterion condensation effect when counterions are allowed to have finite size. Focus is placed on the changes undergone by their concentration in the condensation layer for low-salt and highly charged colloids.
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Affiliation(s)
- F Carrique
- Departamento de Física Aplicada I Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
| | - E Ruiz-Reina
- Departamento de Física Aplicada II Escuela de Ingenierías Industriales Universidad de Málaga, 29071 Málaga, Spain
| | - F J Arroyo
- Departamento de Física Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain
| | - M L Jiménez
- Departamento de Física Aplicada Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - S Ahualli
- Departamento de Física Aplicada Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - A V Delgado
- Departamento de Física Aplicada Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
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Abstract
Hydrogels have three-dimensional network structures, high water content, good flexibility, biocompatibility, and stimulation response, which have provided a unique role in many fields such as industry, agriculture, and medical treatment. Poly(vinyl alcohol) PVA hydrogel is one of the oldest composite hydrogels. It has been extensively explored due to its chemical stability, nontoxic, good biocompatibility, biological aging resistance, high water-absorbing capacity, and easy processing. PVA-based hydrogels have been widely investigated in drug carriers, articular cartilage, wound dressings, tissue engineering, and other intelligent materials, such as self-healing and shape-memory materials, supercapacitors, sensors, and other fields. In this paper, the discovery, development, preparation, modification methods, and applications of PVA functionalized hydrogels are reviewed, and their potential applications and future research trends are also prospected.
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Bakhshandeh A, Segala M, Colla T. Electrolytes in regimes of strong confinement: surface charge modulations, osmotic equilibrium and electroneutrality. SOFT MATTER 2020; 16:10488-10505. [PMID: 33073284 DOI: 10.1039/d0sm01386b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the present work, we study an electrolyte solution confined between planar surfaces with nanopatterned charged domains, which has been connected to a bulk ionic reservoir. The system is investigated through an improved Monte Carlo (MC) simulation method, suitable for simulation of electrolytes in the presence of modulated surface charge distributions. We also employ a linear approach in the spirit of the classical Debye-Hückel approximation, which allows one to obtain explicit expressions for the averaged potentials, ionic profiles, effective surface interactions and the net ionic charge confined between the walls. Emphasis is placed on the limit of strongly confined electrolytes, in which case local electroneutrality in the inter-surface space might not be fulfilled. In order to access the effects of such a lack of local charge neutrality on the ion-induced interactions between surfaces with modulated charge domains, we consider two distinct model systems for the confined electrolyte: one in which a salt reservoir is explicitly taken into account via the osmotic equilibrium with an electrolyte of fixed bulk concentration, and a second one in which the equilibrium with a charge neutral ionic reservoir is implicitly considered. While in the former case the osmotic ion exchange might lead to non-vanishing net charges, in the latter model charge neutrality is enforced through the appearance of an implicit Donnan potential across the charged interfaces. A strong dependence of the ion-induced surface interactions on the employed model system is observed at all surface separations. These findings strongly suggest that due care is to be taken while choosing among different scenarios to describe the ion exchange in electrolytes confined between charged surfaces, even in cases when the monopole (non zero net charge) surface contributions are absent.
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Affiliation(s)
- Amin Bakhshandeh
- Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil. and Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil.
| | - Maximiliano Segala
- Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil.
| | - Thiago Colla
- Instituto de Física, Universidade Federal de Ouro Preto, 35400-000, Ouro Preto, MG, Brazil.
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Carrique F, Ruiz-Reina E, Arroyo FJ, Delgado AV. Influence of ion size effects on the electrokinetics of aqueous salt-free colloids in alternating electric fields. Phys Rev E 2020; 102:032614. [PMID: 33076032 DOI: 10.1103/physreve.102.032614] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/31/2020] [Indexed: 11/07/2022]
Abstract
Electrokinetics is the science of the physical phenomena appearing at the solid-liquid interface of dispersed particles subjected to external fields. Techniques based on electrokinetic phenomena constitute an important set of tools for the electrical characterization of colloids because of their sensitivity to the properties of particle-solution interfaces. Their rigorous description may require inclusion of the effects of finite size of chemical species in the theoretical models, and, particularly in the case of salt-free (no external salt added) aqueous colloids, also consideration of water dissociation and possible carbon dioxide contamination in the aqueous solution. A new ac electrokinetic model is presented for concentrated salt-free spherical colloids for arbitrary characteristics of the particles and aqueous solution, including finite-size effects of chemical species by appropriate modifications of the chemical reaction equations to include such non-ideal aspects. The numerical solution of the electrokinetic equations in an alternating electric field has also been carried out by using a realistic non-equilibrium scenario accounting for association-dissociation processes in the chemical reactions. The results demonstrate the importance of including finite-size effects in the electrokinetic response of the colloid, mainly at high frequencies of the electric field, and for highly charged colloids. Findings of previous models for pointlike ions or for ideal salt-free colloids including finite ion size effects are recovered with the present model, for the appropriate limiting conditions.
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Affiliation(s)
- F Carrique
- Departamento de Física Aplicada II, Facultad de Ciencias Universidad de Málaga, 29071 Málaga, Spain
| | - E Ruiz-Reina
- Departamento de Física Aplicada II, Facultad de Ciencias Universidad de Málaga, 29071 Málaga, Spain
| | - F J Arroyo
- Departamento de Física, Facultad de Ciencias Experimentales Universidad de Jaén, 23071 Jaén, Spain
| | - A V Delgado
- Departamento de Física Aplicada, Facultad de Ciencias Universidad de Granada, 18071 Granada, Spain
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Goh K, Li H, Lam K. Effects of salt- and oxygen-coupled stimuli on the reactive behaviors of hemoglobin-loaded polymeric membranes. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2018.11.139] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Feng Z, Li M, Yan Y, Jihai T, Xiao L, Wanglin L. Novel Electrochemical Method for the Characterization of the Degree of Chirality in Chiral Polyaniline. Chirality 2012; 25:39-42. [DOI: 10.1002/chir.22113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 07/18/2012] [Indexed: 11/09/2022]
Affiliation(s)
- Zhang Feng
- College of Chemistry and Chemical Engineering; Chongqing University; Chongqing; 400030; People's Republic of China
| | - Ma Li
- College of Chemistry and Chemical Engineering; Chongqing University; Chongqing; 400030; People's Republic of China
| | - Yang Yan
- School of Chemistry and Material; Yulin Normal University; Yulin; 537000; People's Republic of China
| | - Tang Jihai
- College of Chemistry and Chemical Engineering; Chongqing University; Chongqing; 400030; People's Republic of China
| | | | - Li Wanglin
- College of Chemistry and Chemical Engineering; Chongqing University; Chongqing; 400030; People's Republic of China
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Barr SA, Panagiotopoulos AZ. Grand-canonical Monte Carlo method for Donnan equilibria. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:016703. [PMID: 23005559 DOI: 10.1103/physreve.86.016703] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Indexed: 06/01/2023]
Abstract
We present a method that enables the direct simulation of Donnan equilibria. The method is based on a grand-canonical Monte Carlo scheme that properly accounts for the unequal partitioning of small ions on the two sides of a semipermeable membrane, and can be used to determine the Donnan electrochemical potential, osmotic pressure, and other system properties. Positive and negative ions are considered separately in the grand-canonical moves. This violates instantaneous charge neutrality, which is usually considered a prerequisite for simulations using the Ewald sum to compute the long-range charge-charge interactions. In this work, we show that if the system is neutral only in an average sense, it is still possible to get reliable results in grand-canonical simulations of electrolytes performed with Ewald summation of electrostatic interactions. We compare our Donnan method with a theory that accounts for differential partitioning of the salt, and find excellent agreement for the electrochemical potential, the osmotic pressure, and the salt concentrations on the two sides. We also compare our method with experimental results for a system of charged colloids confined by a semipermeable membrane and to a constant-NVT simulation method, which does not account for salt partitioning. Our results for the Donnan potential are much closer to the experimental results than the constant-NVT method, highlighting the important effect of salt partitioning on the Donnan potential.
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Affiliation(s)
- S A Barr
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
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Feng Z, Li M, Yan Y, Jihai T, Xiao L, Wei Q. Several novel and effective methods for chiral polyaniline to recognize the configuration of alanine. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.tetasy.2012.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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