Isothermal adsorption of polyampholytes on charged nanopatterned surfaces

Bakhshandeh, Amin; Santos, Alexandre Pereira dos; Diehl, Alexandre; Levin, Yan

doi:10.1063/1.5115404

Cited by 9 publications

(12 citation statements)

References 38 publications

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“…The effects of surface-charge heterogeneity on the interaction between a pair of charged surfaces in solution have been investigated in several theoretical works [57][58][59][60][61][62][63][64][65]. The general approach is to find the electrostatic potential and relate it to the osmotic pressure between the surfaces, Π.…”

Section: Interaction Between Heterogeneously Charged Surfacesmentioning

confidence: 99%

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Electrostatics of patchy surfaces

Adar

Andelman

Diamant

2017

Advances in Colloid and Interface Science

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In the study of colloidal, biological and electrochemical systems, it is customary to treat surfaces, macromolecules and electrodes as homogeneously charged. This simplified approach is proven successful in most cases, but fails to describe a wide range of heterogeneously charged surfaces commonly used in experiments. For example, recent experiments have revealed a long-range attraction between overall neutral surfaces, locally charged in a mosaic-like structure of positively and negatively charged domains ("patches"). Here we review experimental and theoretical studies addressing the stability of heterogeneously charged surfaces, their ionic strength in solution, and the interaction between two such surfaces. We focus on electrostatics, and highlight the important new physical parameters appearing in the heterogeneous case, such as the largest patch size and inter-surface charge correlations.

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Section: Interaction Between Heterogeneously Charged Surfacesmentioning

confidence: 99%

“…The forces between patchy surfaces were recently tested in MC simulations [65] for strongly charged patches and weak ionic strength. In the simulations, surfaces of area ∼ 1, 500 nm 2 were divided into two or four patches, charged alternatively with positive or negative charges.…”

Section: Overall Neutral and Randomly Charged Surfacesmentioning

confidence: 99%

Electrostatics of patchy surfaces

Adar

Andelman

Diamant

2017

Advances in Colloid and Interface Science

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“…There are basically two experimental routes in which this grafting process may take place: one in which the whole chain is attached at the surface via chemical bonds (the socalled grafting-to process) and a second one in which free monomers are first attracted to specific surface sites, followed by a polymerization process in which the remaining free monomers are progressively linked together to these initially formed monolayers (e. g., via highly directional, short-ranged interactions), until the fully assembled chains are found in equilibrium with the free, dissociated monomers (the so-called grafting-from process 55,56 ). Electrostatic interactions are usually of great relevance for driving (and further stabilizing) these processes [57][58][59][60][61][62][63] . They are one of the main driven forces that controls the so-called charge-regulation mechanisms, responsible for the binding/dissociation of ions into/from surface functional groups in an aqueous environment containing acidic/basic dissociated ions [64][65][66][67][68][69][70][71][72] .…”

Section: Introductionmentioning

confidence: 99%

Equilibrium conformations and surface charge regulation of spherical polymer brushes in stretched regimes

Bakhshandeh,

Segala,

Colla

2021

Preprint

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In the present work, we study the equilibrium conformations of linear polyelectrolytes tethered onto a spherical, oppositely charged core in equilibrium with an ionic reservoir of fixed concentration. Particular focus is placed on the situation of stretched chains, where the monomer concentration is known to display an inverse square-law decay far away from the spherical surface, which is then further extrapolated all the way down to the grafting core. While the equilibrium distributions of mobile ions are computed in the framework of a classical Density Functional Theory (cDFT) that incorporates both their size and electrostatic correlations within the grafted polyelectrolyte, the equilibrium configuration of the latter is described by its averaged radius of gyration, which is taken as a variational parameter that guarantees mechanical equilibrium across the polymer-solvent interface. The averaged particle size is then analyzed over a wide range of polymerization degrees, ionic concentrations and functionality of the polymer backbones. Two distinct regimes can be identified: at high ionic strengths, swelling of the grafted polymers is dominated by ionic entropic contribution as well as polymer size effects, whereas at low ionic concentrations a balance between electrostatic and entropic effects is the main driven mechanism for particle stretching. Using Monte Carlo simulations, we then proceed to investigate the effects of charge regulation when the brush core is further decorated with active functional sites randomly distributed over its surface, which act as receptors onto which dissolved acidic ions can be adsorbed.

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“…Even though the inclusion of such effects might significantly increase the complexity in the system description, realistic approaches of the interactions of charged surfaces requires the incorporation of such effects, as many of the technologically relevant charged systems are comprised of patchy-like surface charge domains. One example are charged surfaces made of nano-patterned charge modulations [38], which can be designed via nano-fabrication techniques [39,40]. These systems have recently attracted a lot of attention due to their potential application in the production of nano-technological devices and biological systems [41].…”

Section: Introductionmentioning

confidence: 99%

Electrolytes in regimes of strong confinements: surface charge modulations, osmotic equilibrium and electroneutrality

Bakhshandeh,

Segala,

Colla

2020

Preprint

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In the present work, we study an electrolyte solution confined between planar surfaces with nonopatterned 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 in 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 lack of local charge neutrality on the ionic-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 ionic 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 ionic-induced surface interactions in the employed model system is observed at all particle separations. These findings strongly suggest that due care is to be taken while choosing among different scenarios to describe the ionic exchanging in electrolytes confined between charged surfaces, even in cases when the monopole (non zero net charge) surface contributions are absent.

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Isothermal adsorption of polyampholytes on charged nanopatterned surfaces

Abstract: Compressing physics with an autoencoder: Creating an atomic species representation to improve machine learning models in the chemical sciences

Cited by 9 publications

References 38 publications

Electrostatics of patchy surfaces

Electrostatics of patchy surfaces

Equilibrium conformations and surface charge regulation of spherical polymer brushes in stretched regimes

Electrolytes in regimes of strong confinements: surface charge modulations, osmotic equilibrium and electroneutrality

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