1
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Ishraaq R, Das S. All-atom molecular dynamics simulations of polymer and polyelectrolyte brushes. Chem Commun (Camb) 2024; 60:6093-6129. [PMID: 38819435 DOI: 10.1039/d4cc01557f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Densely grafted polymer and polyelectrolyte (PE) brushes, owing to their significant abilities to functionalize surfaces for a plethora of applications in sensing, diagnostics, current rectification, surface wettability modification, drug delivery, and oil recovery, have attracted significant attention over the past several decades. Unfortunately, most of the attention has primarily focused on understanding the properties of the grafted polymer and the PE chains with little attention devoted to studying the behavior of the brush-supported ions (counterions needed to screen the PE chains) and water molecules. Over the past few years, our group has been at the forefront of addressing this gap: we have employed all-atom molecular dynamics (MD) simulations for studying a wide variety of polymer and PE brush systems with specific attention to unraveling the properties and behavior of the brush-supported water molecules and ions. Our findings have revealed some of the most fascinating properties of such brush-supported ions and water molecules, including the most remarkable control of nanofluidic transport afforded by the specific ion and water responses induced by the PE brushes grafted on the inner walls of the nanochannel. This feature article aims to summarize some of our key contributions associated with such atomistic simulations of polymer and PE brushes and brush-supported water molecules and counterions.
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Affiliation(s)
- Raashiq Ishraaq
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA.
| | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA.
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2
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Sin JS. Structural and electrostatic properties between pH-responsive polyelectrolyte brushes studied by augmented strong stretching theory. J Chem Phys 2022; 157:084902. [DOI: 10.1063/5.0097783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this paper, we study electrostatic and structural properties between pH-responsive polyelectrolyte brushes by using a strong stretching theory accounting for excluded volume interactions, the density of polyelectrolyte chargeable sites and the Born energy difference between the inside and outside of the brush layer.In a free energy framework, we obtain self-consistent field equations to determine electrostatic properties between two pH-responsive polyelectrolyte brushes. We elucidate that in the region between two pH-responsive polyelectrolyte brushes, electrostatic potential at the centerline and osmotic pressure increase not only with excluded volume interaction, but also with density of chargeable sites on a polyelectrolyte molecule. Importantly, we clarify that when two pH-responsive polyelectrolyte brushes approach each other, the brush thickness becomes short and that a large excluded volume interaction and a large density of chargeable sites yield the enhanced contract of polyelectrolyte brushes. In addition, we also demonstrate how the influence of such quantities as pH, the number of Kuhn monomers, the density of charged sites, the lateral separation between adjacent polyelectrolyte brushes, Kuhn length on the electrostatic and structural properties between the two polyelectrolyte brushes is affected by the exclusion volume interaction. Finally, we investigate the influence of Born energy difference on the thickness of polyelectrolyte brushes and the osmotic pressure between two pH-responsive polyelectrolyte brushes.
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Affiliation(s)
- Jun-Sik Sin
- Natural Science Center, Kim Il Sung University, Korea, Democratic People's Republic of (North Korea)
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3
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Filipović U, Dahmane RG, Ghannouchi S, Zore A, Bohinc K. Bacterial adhesion on orthopedic implants. Adv Colloid Interface Sci 2020; 283:102228. [PMID: 32858407 DOI: 10.1016/j.cis.2020.102228] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 01/19/2023]
Abstract
Orthopedic implants are routinely used for fixation of fractures, correction of deformities, joint replacements, and soft tissue anchorage. Different biomaterials have been engineered for orthopedic implants. Previously, they were designed merely as mechanical devices, now new strategies to enhance bone healing and implant osteointegration via local delivery of molecules and via implant coatings are being developed. These biological coatings should enhance osteointegration and reduce foreign body response or infection. This article reviews current and future orthopedic implants, materials and surface characteristics, biocompatibility, and mechanisms of bacterial adhesion. Additionally, the review is addressing implant-related infection, the main strategies to prevent it and suggest possible future research that may control implant related-infection.
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Affiliation(s)
- Urška Filipović
- University Clinical Center of Ljubljana, Department of Traumatology, Zaloska 7, 1000 Ljubljana, Slovenia
| | - Raja Gošnak Dahmane
- University of Ljubljana, Faculty of Health Sciences, Zdravstvena pot 5, 1000 Ljubljana, Slovenia; University of Ljubljana, Faculty of Medicine, Institute of Anatomy, Korytkova 2, 1000 Ljubljana, Slovenia
| | | | - Anamarija Zore
- University of Ljubljana, Faculty of Health Sciences, Zdravstvena pot 5, 1000 Ljubljana, Slovenia
| | - Klemen Bohinc
- University of Ljubljana, Faculty of Health Sciences, Zdravstvena pot 5, 1000 Ljubljana, Slovenia.
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4
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Sivasankar VS, Etha SA, Sachar HS, Das S. Theoretical study on the massively augmented electro-osmotic water transport in polyelectrolyte brush functionalized nanoslits. Phys Rev E 2020; 102:013103. [PMID: 32794997 DOI: 10.1103/physreve.102.013103] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/08/2020] [Indexed: 11/07/2022]
Abstract
We demonstrate that functionalizing nanoslits with pH-responsive polyelectrolyte brushes can lead to extremely fast electro-osmotic (EOS) water transport, where the maximum centreline velocity and the volume flow rate can be an order of magnitude larger than these quantities in identically charged brush-free nanochannels for a wide range of system parameters. Such an enhancement is most remarkable given that the brushes have been known to retard the transport by imparting additional drag on the fluid flow. We argue that this enhancement stems from the localization of the charge density of the brush-induced electric double layer (and, hence, the EOS body force) away from the nanochannel wall (or the location of the wall-induced drag force). This ensures a much larger impact of the EOS body force triggering such fast water transport. Finally, the calculated flux values for the present brush-grafted nanochannels are found to be significantly larger than those for a wide range of nanofluidic membranes and channels, suggesting that the brush functionalization can be considered as a mechanism for enabling such superfast nanofluidic transport.
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Affiliation(s)
| | - Sai Ankit Etha
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Harnoor Singh Sachar
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, USA
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5
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Asmawi AA, Salim N, Abdulmalek E, Abdul Rahman MB. Modeling the Effect of Composition on Formation of Aerosolized Nanoemulsion System Encapsulating Docetaxel and Curcumin Using D-Optimal Mixture Experimental Design. Int J Mol Sci 2020; 21:E4357. [PMID: 32575390 PMCID: PMC7352744 DOI: 10.3390/ijms21124357] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/07/2020] [Accepted: 06/11/2020] [Indexed: 02/03/2023] Open
Abstract
The synergistic anticancer effect of docetaxel (DTX) and curcumin (CCM) has emerged as an attractive therapeutic candidate for lung cancer treatment. However, the lack of optimal bioavailability because of high toxicity, low stability, and poor solubility has limited their clinical success. Given this, an aerosolized nanoemulsion system for pulmonary delivery is recommended to mitigate these drawbacks. In this study, DTX- and CCM-loaded nanoemulsions were optimized using the D-optimal mixture experimental design (MED). The effect of nanoemulsion compositions towards two response variables, namely, particle size and aerosol size, was studied. The optimized formulations for both DTX- and CCM-loaded nanoemulsions were determined, and their physicochemical and aerodynamic properties were evaluated as well. The MED models achieved the optimum formulation for DTX- and CCM-loaded nanoemulsions containing a 6.0 wt% mixture of palm kernel oil ester (PKOE) and safflower seed oils (1:1), 2.5 wt% of lecithin, 2.0 wt% mixture of Tween 85 and Span 85 (9:1), and 2.5 wt% of glycerol in the aqueous phase. The actual values of the optimized formulations were in line with the predicted values obtained from the MED, and they exhibited desirable attributes of physicochemical and aerodynamic properties for inhalation therapy. Thus, the optimized formulations have potential use as a drug delivery system for a pulmonary application.
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Affiliation(s)
- Azren Aida Asmawi
- Integrated Chemical BioPhysics Research, Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.A.); (N.S.); (E.A.)
| | - Norazlinaliza Salim
- Integrated Chemical BioPhysics Research, Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.A.); (N.S.); (E.A.)
| | - Emilia Abdulmalek
- Integrated Chemical BioPhysics Research, Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.A.); (N.S.); (E.A.)
| | - Mohd Basyaruddin Abdul Rahman
- Integrated Chemical BioPhysics Research, Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.A.); (N.S.); (E.A.)
- UPM-MAKNA Cancer Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
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6
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Etha SA, Sivasankar VS, Sachar HS, Das S. Strong stretching theory for pH-responsive polyelectrolyte brushes in large salt concentrations. Phys Chem Chem Phys 2020; 22:13536-13553. [DOI: 10.1039/d0cp02099k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we develop a theory for describing the thermodynamics, configuration, and electrostatics of strongly-stretched, pH-responsive polyelectrolyte (PE) brushes in the presence of large salt concentrations.
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Affiliation(s)
- Sai Ankit Etha
- Department of Mechanical Engineering
- University of Maryland
- College Park
- USA
| | | | | | - Siddhartha Das
- Department of Mechanical Engineering
- University of Maryland
- College Park
- USA
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7
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Gorthi SR, Gaikwad HS, Mondal PK, Biswas G. Surface Tension Driven Filling in a Soft Microchannel: Role of Streaming Potential. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00767] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Srinivas R. Gorthi
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam, India 781039
| | - Harshad Sanjay Gaikwad
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam, India 781039
| | - Pranab Kumar Mondal
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam, India 781039
| | - Gautam Biswas
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam, India 781039
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8
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Sachar HS, Sivasankar VS, Das S. Revisiting the strong stretching theory for pH-responsive polyelectrolyte brushes: effects of consideration of excluded volume interactions and an expanded form of the mass action law. SOFT MATTER 2019; 15:559-574. [PMID: 30520929 DOI: 10.1039/c8sm02163e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this paper, we develop a theory to account for the effect of excluded volume (EV) interactions in the strong stretching theory (SST) based description of pH-responsive polyelectrolyte (PE) brushes. The existing studies have considered the PE brushes to be present in a θ-solvent and hence have neglected the EV interactions; however, such a consideration cannot describe the situations where the pH-responsive brushes are in a "good" solvent. Secondly, we consider a more expanded form of the mass action law, governing the pH-dependent ionization of the PE molecules, in the SST description of the PE brushes. This expanded form of the mass action law considers different values of γa3 (γ is the density of chargeable sites on the PE molecule and a is the PE Kuhn length) and therefore is an improvement over the existing SST models of PE brushes as well as other theories involving pH-responsive PE molecules that always consider γa3 = 1. Our results demonstrate that the EV effects enhance the brush height by inducing additional PE inter-segmental repulsion. Similarly, the consideration of the expanded form of the mass action law would lead to a reduced (enhanced) brush height for γa3 < 1 (γa3 > 1). We also quantify variables such as the monomer density distribution, the distribution of the ends of the PE brush, and the EDL electrostatic potential and explain their differences with respect to those obtained with no EV interactions or γa3 = 1.
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Affiliation(s)
- Harnoor Singh Sachar
- Department of Mechanical Engineering, University of Maryland, College Park, MD-20742, USA.
| | | | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, MD-20742, USA.
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9
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The role of ion partitioning in electrohydrodynamic characteristics of soft nanofluidics: Inclusion of EDL overlap and steric effects. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2018.05.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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10
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Chen G, Sachar HS, Das S. Efficient electrochemomechanical energy conversion in nanochannels grafted with end-charged polyelectrolyte brushes at medium and high salt concentration. SOFT MATTER 2018; 14:5246-5255. [PMID: 29888349 DOI: 10.1039/c8sm00768c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We develop a theory to study the generation of the streaming potential and the resulting electrochemomechanical energy conversion (ECMEC) in the presence of pressure-driven transport in nanochannels grafted with end-charged polyelectrolyte (PE) brushes. Our theory gives a thermodynamically self-consistent coupled description of the PE-brush and the electrostatics of the electric double layer (EDL) induced by the PE charges. The end-charged brushes localize the maximum EDL charge density away from the wall, thereby enabling a larger magnitude of pressure-driven transport to stream the ions downstream. This effect is retarded by the drag force imparted by the brushes as well as by the enhanced electroosmotic transport in a direction opposite to the pressure-driven transport. An interplay of these three issues leads to highly non-trivial electrohydrodynamic transport that eventually allows us to converge on appropriate properties of the brushes (e.g., grafting density and the number of monomers) that lead to the generation of a significantly larger streaming potential and a much improved efficiency of the ECMEC as compared to the brush-free nanochannels particularly at medium and high salt concentrations.
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Affiliation(s)
- Guang Chen
- Department of Mechanical Engineering, University of Maryland, College Park, MD-20742, USA.
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11
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Ganjizade A, Sadeghi A, Ashrafizadeh SN. Effect of ion partitioning on electrostatics of soft particles with volumetrically charged inner core coated with pH-regulated polyelectrolyte layer. Colloids Surf B Biointerfaces 2018; 170:129-135. [PMID: 29894833 DOI: 10.1016/j.colsurfb.2018.05.053] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 05/09/2018] [Accepted: 05/23/2018] [Indexed: 01/18/2023]
Abstract
The effect of ion partitioning on the electrostatics of a soft particle with a volumetrically charged core and a pH-dependent polyelectrolyte layer (PEL) is numerically investigated. It is observed that, whenever the ion partitioning is noticeable, the soft layer can be fully charged in a broader range of pH. Besides, a higher number density of the PEL functional groups and a lower charge density of the core result in a sharper dependence of the electric potential on the electrolyte pH. Briefly, we conclude that, since the PEL charge is dependent upon the concentration of the hydroxide/hydrogen ions, for the pH-regulated soft particles, the ion partitioning effect, as a phenomenon influencing the ionic distribution, can be a determinant factor. So taking the effect of the ion partitioning into consideration is strongly recommended for a more realistic description of the electrostatics of the pH-regulated soft particles.
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Affiliation(s)
- Ardalan Ganjizade
- Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
| | - Arman Sadeghi
- Department of Mechanical Engineering, University of Kurdistan, Sanandaj 66177-15175, Iran.
| | - Seyed Nezameddin Ashrafizadeh
- Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
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12
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Sin JS, Kim UH. Ion size effect on electrostatic and electroosmotic properties in soft nanochannels with pH-dependent charge density. Phys Chem Chem Phys 2018; 20:22961-22971. [DOI: 10.1039/c8cp04185g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a theoretical study of the ion size effect on various properties in a soft nanochannel with pH-dependent charge density.
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Affiliation(s)
- Jun-Sik Sin
- Department of Physics, Kim Il Sung University
- Pyongyang
- Democratic People's Republic of Korea
- Natural Science Center, Kim Il Sung University
- Pyongyang
| | - Un-Hyok Kim
- Institute of Environmental Science and Water Technology, Academy of Sciences
- Pyongyang
- Democratic People's Republic of Korea
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13
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Sin JS, Kim NH, Sin CS. Effect of solvent polarization on electric double layer of a charged soft surface in an electrolyte solution. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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14
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Alternating current electroosmotic flow in polyelectrolyte-grafted nanochannel. Colloids Surf B Biointerfaces 2016; 147:234-241. [DOI: 10.1016/j.colsurfb.2016.07.064] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/16/2016] [Accepted: 07/31/2016] [Indexed: 11/23/2022]
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15
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Li H, Chen G, Das S. Electric double layer electrostatics of pH-responsive spherical polyelectrolyte brushes in the decoupled regime. Colloids Surf B Biointerfaces 2016; 147:180-190. [DOI: 10.1016/j.colsurfb.2016.07.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/20/2016] [Accepted: 07/25/2016] [Indexed: 11/29/2022]
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16
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Poddar A, Maity D, Bandopadhyay A, Chakraborty S. Electrokinetics in polyelectrolyte grafted nanofluidic channels modulated by the ion partitioning effect. SOFT MATTER 2016; 12:5968-5978. [PMID: 27306568 DOI: 10.1039/c6sm00275g] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The effects of ion partitioning on the electrokinetics in a polyelectrolyte grafted nanochannel, which is the representative of a soft nanochannel, are analyzed. Earlier studies in this regard have considered low polyelectrolyte layer (PEL) grafting density at the rigid nanochannel wall and, hence, an equal permittivity inside and outside the grafted layer. In order to overcome this shortcoming, the concept of Born energy is revisited. The coupled system of the modified Poisson-Boltzmann and Navier-Stokes equation is solved numerically, going beyond the widely employed Debye-Hückel linearization and low PEL densities. The complex interplay between the hydrodynamics and charge distribution, modulated by the ion partitioning effect, along with their consequent effects on the streaming potential and electrokinetic energy conversion efficiency (EKEC) have been systemically investigated. It has been observed that the ion partitioning effect reduces the EKEC in comparison to the case with equal permittivity up to a certain electrical double layer thickness after which it increases the EKEC. For a high concentration of mobile charges within the PEL, the net gain in the maximum EKEC due to the ion partitioning effect is about 10 fold that of the case when the ion partitioning effect is not considered. We delve into the various scaling regimes in the streaming potential and intriguingly point out the exact location of peaks in efficiency. The present study also reveals the possibility of improvement in streaming potential mediated energy conversion by the use of polyelectrolyte materials, which possess substantially lower dielectric permittivity than the bulk electrolyte.
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Affiliation(s)
- Antarip Poddar
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India-721302.
| | - Debonil Maity
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India-721302.
| | - Aditya Bandopadhyay
- Advanced Technology Development Center, Indian Institute of Technology Kharagpur, Kharagpur, India-721302
| | - Suman Chakraborty
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India-721302. and Advanced Technology Development Center, Indian Institute of Technology Kharagpur, Kharagpur, India-721302
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Chen G, Das S. Anomalous Shrinking–Swelling of Nanoconfined End-Charged Polyelectrolyte Brushes: Interplay of Confinement and Electrostatic Effects. J Phys Chem B 2016; 120:6848-57. [DOI: 10.1021/acs.jpcb.6b04636] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Guang Chen
- Department
of Mechanical
Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Siddhartha Das
- Department
of Mechanical
Engineering, University of Maryland, College Park, Maryland 20742, United States
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18
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Barbati AC, Kirby BJ. Surface conductivity in electrokinetic systems with porous and charged interfaces: Analytical approximations and numerical results. Electrophoresis 2016; 37:1979-91. [PMID: 27168464 DOI: 10.1002/elps.201500505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 11/10/2022]
Abstract
We derive an approximate analytical representation of the conductivity for a 1D system with porous and charged layers grafted onto parallel plates. Our theory improves on prior work by developing approximate analytical expressions applicable over an arbitrary range of potentials, both large and small as compared to the thermal voltage (RTF). Further, we describe these results in a framework of simplifying nondimensional parameters, indicating the relative dominance of various physicochemical processes. We demonstrate the efficacy of our approximate expression with comparisons to numerical representations of the exact analytical conductivity. Finally, we utilize this conductivity expression, in concert with other components of the electrokinetic coupling matrix, to describe the streaming potential and electroviscous effect in systems with porous and charged layers.
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Affiliation(s)
- Alexander C Barbati
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
| | - Brian J Kirby
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
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19
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Das S, Banik M, Chen G, Sinha S, Mukherjee R. Polyelectrolyte brushes: theory, modelling, synthesis and applications. SOFT MATTER 2015; 11:8550-83. [PMID: 26399305 DOI: 10.1039/c5sm01962a] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Polyelectrolyte (PE) brushes are a special class of polymer brushes (PBs) containing charges. Polymer chains attain "brush"-like configuration when they are grafted or get localized at an interface (solid-fluid or liquid-fluid) with sufficiently close proximity between two-adjacent grafted polymer chains - such a proximity triggers a particular nature of interaction between the adjacent polymer molecules forcing them to stretch orthogonally to the grafting interface, instead of random-coil arrangement. In this review, we discuss the theory, synthesis, and applications of PE brushes. The theoretical discussion starts with the standard scaling concepts for polymer and PE brushes; following that, we shed light on the state of the art in continuum modelling approaches for polymer and PE brushes directed towards analysis beyond the scaling calculations. A special emphasis is laid in pinpointing the cases for which the PE electrostatic effects can be de-coupled from the PE entropic and excluded volume effects; such de-coupling is necessary to appropriately probe the complicated electrostatic effects arising from pH-dependent charging of the PE brushes and the use of these effects for driving liquid and ion transport at the interfaces covered with PE brushes. We also discuss the atomistic simulation approaches for polymer and PE brushes. Next we provide a detailed review of the existing approaches for the synthesis of polymer and PE brushes on interfaces, nanoparticles, and nanochannels, including mixed brushes and patterned brushes. Finally, we discuss some of the possible applications and future developments of polymer and PE brushes grafted on a variety of interfaces.
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Affiliation(s)
- Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, MD-20742, USA.
| | - Meneka Banik
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Pin - 721302, Kharagpur, West Bengal, India
| | - Guang Chen
- Department of Mechanical Engineering, University of Maryland, College Park, MD-20742, USA.
| | - Shayandev Sinha
- Department of Mechanical Engineering, University of Maryland, College Park, MD-20742, USA.
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Pin - 721302, Kharagpur, West Bengal, India
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20
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Chen G, Das S. Scaling Laws and Ionic Current Inversion in Polyelectrolyte-Grafted Nanochannels. J Phys Chem B 2015; 119:12714-26. [DOI: 10.1021/acs.jpcb.5b07167] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Guang Chen
- Department of Mechanical
Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Siddhartha Das
- Department of Mechanical
Engineering, University of Maryland, College Park, Maryland 20742, United States
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21
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McDaniel K, Valcius F, Andrews J, Das S. Electrostatic potential distribution of a soft spherical particle with a charged core and pH-dependent charge density. Colloids Surf B Biointerfaces 2015; 127:143-7. [DOI: 10.1016/j.colsurfb.2015.01.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/11/2015] [Accepted: 01/14/2015] [Indexed: 10/24/2022]
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