1
|
Dolatkhah A, Dewani C, Kazem-Rostami M, Wilson LD. Magnetic Silver Nanoparticles Stabilized by Superhydrophilic Polymer Brushes with Exceptional Kinetics and Catalysis. Polymers (Basel) 2024; 16:2500. [PMID: 39274133 PMCID: PMC11398182 DOI: 10.3390/polym16172500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 08/27/2024] [Accepted: 08/31/2024] [Indexed: 09/16/2024] Open
Abstract
Stimuli-responsive catalysts with exceptional kinetics and complete recoverability for efficient recyclability are essential in, for example, converting pollutants and hazardous organic compounds into less harmful chemicals. Here, we used a novel approach to stabilize silver nanoparticles (NPs) through magneto/hydro-responsive anionic polymer brushes that consist of poly (acrylic acid) (PAA) moieties at the amine functional groups of chitosan. Two types of responsive catalyst systems with variable silver loading (wt.%) of high and low (PAAgCHI/Fe3O4/Ag (H, L)) were prepared. The catalytic activity was evaluated by monitoring the reduction of organic dye compounds, 4-nitrophenol and methyl orange in the presence of NaBH4. The high dispersity and hydrophilic nature of the catalyst provided exceptional kinetics for dye reduction that surpassed previously reported nanocatalysts for organic dye reduction. Dynamic light scattering (DLS) measurements were carried out to study the colloidal stability of the nanocatalysts. The hybrid materials not only showed enhanced colloidal stability due to electrostatic repulsion among adjacent polymer brushes but also offered more rapid kinetics when compared with as-prepared Ag nanoparticles (AgNPs), which results from super-hydrophilicity and easy accumulation/diffusion of dye species within polymer brushes. Such remarkable kinetics, biodegradability, biocompatibility, low cost and facile magnetic recoverability of the Ag nanocatalysts reported here contribute to their ranking among the top catalyst systems reported in the literature. It was observed that the apparent catalytic rate constant for the reduction of methyl orange dye was enhanced, PAAgCHI/Fe3O4/Ag (H) ca. 35-fold and PAAgCHI/Fe3O4/Ag (L) ca. 23-fold, when compared against the as prepared AgNPs. Finally, the regeneration and recyclability of the nanocatalyst systems were studied over 15 consecutive cycles. It was demonstrated that the nanomaterials display excellent recyclability without a notable loss in catalytic activity.
Collapse
Affiliation(s)
- Asghar Dolatkhah
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Chandni Dewani
- Department of Chemical Engineering, Malaviya National Institute of Technology Jaipur, Jawahar Lal Nehru Marg, Jhalana Gram, Malviya Nagar, Jaipur 302017, Rajasthan, India
| | - Masoud Kazem-Rostami
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Faculty of Science and Engineering, Macquarie University, North Ryde, NSW 2109, Australia
| | - Lee D Wilson
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| |
Collapse
|
2
|
Dhibaris S, Pal S, Some S, Karmakar K, Saha R, Bhattacharjee S, Roy A, Ray SJ, Ajiboye TO, Dam S, Saha B. Efficient antimicrobial applications of two novel supramolecular metallogels derived from a l(+)-tartaric acid low molecular weight gelator. RSC Adv 2024; 14:26354-26361. [PMID: 39165795 PMCID: PMC11334155 DOI: 10.1039/d4ra03451a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 08/09/2024] [Indexed: 08/22/2024] Open
Abstract
Novel metallogels were synthesized using l(+)-tartaric acid as a gelator, along with cadmium(ii)-acetate and mercury(ii)-acetate in N,N-dimethyl formamide at room temperature. Rheological analyses confirmed the mechanical stability of Cd(ii)- and Hg(ii)-metallogels under varying conditions. Characterization through EDX mapping and FESEM imaging provided insights into their chemical constituents and microstructural features. FT-IR spectroscopy elucidated the metallogel formation mechanism. Antimicrobial assays revealed significant activity against various bacteria, including Gram-positive and Gram-negative strains. This study presents a comprehensive exploration of Cd(ii) and Hg(ii)-based l(+)-tartaric acid-mediated metallogels, highlighting their potential in combating bacterial infections. These findings suggest promising applications in both industrial and biomedical fields, offering avenues for the development of advanced materials.
Collapse
Affiliation(s)
- Subhendu Dhibaris
- Colloid Chemistry Laboratory, Department of Chemistry, The University of Burdwan Golapbag Burdwan 713104 West Bengal India +91 7001575909 +91 9476341691
| | - Suchetana Pal
- Department of Microbiology, The University of Burdwan Burdwan 713104 West Bengal India
| | - Sangita Some
- Colloid Chemistry Laboratory, Department of Chemistry, The University of Burdwan Golapbag Burdwan 713104 West Bengal India +91 7001575909 +91 9476341691
| | - Kripasindhu Karmakar
- Colloid Chemistry Laboratory, Department of Chemistry, The University of Burdwan Golapbag Burdwan 713104 West Bengal India +91 7001575909 +91 9476341691
| | - Ratnakar Saha
- National Institute of Science Education and Research (NISER) Bhubaneswar Odisha 752050 India
| | - Subham Bhattacharjee
- Department of Chemistry, Kazi Nazrul University Asansol 713303 West Bengal India
| | - Arpita Roy
- Department of Physics, Indian Institute of Technology Patna Bihar 801106 India
| | - Soumya Jyoti Ray
- Department of Physics, Indian Institute of Technology Patna Bihar 801106 India
| | - Timothy O Ajiboye
- Department of Chemistry, University of the Free State Bloemfontein 9301 South Africa
| | - Somasri Dam
- Department of Microbiology, The University of Burdwan Burdwan 713104 West Bengal India
| | - Bidyut Saha
- Colloid Chemistry Laboratory, Department of Chemistry, The University of Burdwan Golapbag Burdwan 713104 West Bengal India +91 7001575909 +91 9476341691
| |
Collapse
|
3
|
Saha B, Chowdhury S, Sarkar S, Gopmandal PP. Electroosmotic flow modulation and dispersion of uncharged solutes in soft nanochannel. SOFT MATTER 2024; 20:6458-6489. [PMID: 39091251 DOI: 10.1039/d4sm00614c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
We perform a systematic study on the modulation of electroosmotic flow (EOF), tuning the selectivity using electrolyte ions and hydrodynamic dispersion of the solute band across the soft nanochannel. The supporting walls of the channel are considered to be hydrophobic and bear non-zero surface charge. For such a channel, the inner side of the supporting rigid walls of the channel are coated with a soft polyelectrolyte layer (PEL). The inhomogeneous distribution of monomers and accompanying volume charge within the PEL is modelled via soft-step function. The dielectric permittivity of the PEL and electrolyte solution are in general different, which in turn leads to the ion partitioning effect. The impact of ion steric effects due to finite sized ions is further accounted through the modified ion activity coefficient. To model the EOF modulation considering the combined impact of the ion steric and ion partitioning effects as well as inhomogeneous distribution of monomers across the PEL, we adopt the modified Poisson-Boltzmann equation as the governing equation for electrostatic potential. The Debye-Bueche model is adopted to study the flow field across the PEL and the Stokes equation governs the EOF outside the PEL. In order to study the impact of the modulated EOF field on the dispersion of uncharged solution, we adopt three different models, i.e., a general 2D convective-diffusion model as well as cross-sectional averaged dispersion models due to Gill and late-time Taylor and Aris. Going beyond the widely employed Debye-Hückel approximation and uniform distribution of the monomer as well as accompanying volume charge, we find the results for the electric double layer (EDL) potential, EOF field and averaged throughput, by tuning the ion selectivity, etc., which is sufficient to analyze the transport of ionized liquid across the channel. The numerical results are supplemented with analytical results for the EDL potential as well as the EOF field under various limiting situations. Besides, we have further shown the impact of the modulated EOF field on the solute dispersion process. We have presented results that highlight the impact of parameters related to EOF field modulation, on solute dispersion governed by a convective-diffusive process, as well as obtaining the results for an effective dispersion coefficient. The dispersion models under the modulated EOF field adopted in the present study can thus be applied to study the dispersion process in engineered microdevices.
Collapse
Affiliation(s)
- Biswadip Saha
- Physics and Applied Mathematics Unit, Indian Statistical Institute Kolkata, Kolkata-700108, India
| | - Sourav Chowdhury
- Department of Mathematics, National Institute of Technology Durgapur, Durgapur-713209, India.
| | - Sankar Sarkar
- Physics and Applied Mathematics Unit, Indian Statistical Institute Kolkata, Kolkata-700108, India
| | - Partha P Gopmandal
- Department of Mathematics, National Institute of Technology Durgapur, Durgapur-713209, India.
| |
Collapse
|
4
|
Duan C, Wang R. Ion Correlation-Driven Hysteretic Adhesion and Repulsion between Opposing Polyelectrolyte Brushes. ACS Macro Lett 2024:1127-1132. [PMID: 39141897 DOI: 10.1021/acsmacrolett.4c00426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Polyelectrolyte (PE) brushes are widely used in biomaterials and nanotechnology to regulate the surface properties and interactions. Here, we apply the electrostatic correlation augmented self-consistent field theory to investigate the interactions between opposing PE brushes in a mixture of 1:1 and 3:1 salt solutions. Our theory predicts a hysteretic feature of the normal stress induced by strong ion correlations. In the presence of trivalent ions, the force profile is discontinuous: repulsive in the compression branch and adhesive in the separation branch. The molecular origin of the hysteretic force is the coexistence of two collapsed modes: two separated condensed layers on each surface in the compression and a single bundled condensed layer in the separation. With the systematic inclusion of ion correlations, our theory captures well the hysteretic force, adhesive separation, "jump-in" and "jump-out" features, and the "specific ion effect", all in good agreement with the reported experimental results.
Collapse
Affiliation(s)
- Chao Duan
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Rui Wang
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Smith JD, Chen R, Osores NN, Gopalan P. Porous Morphology of High Grafting Density Mixed Polyelectrolyte Brushes Grown from a Y-Inimer Coating. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:10623-10633. [PMID: 38726951 DOI: 10.1021/acs.langmuir.4c00556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Mixed A/B polyelectrolyte (PE) brushes of opposite charges are grown from a Y-shaped initiator-bearing coating to facilitate intimate mixing of the A and B polyelectrolytes in a 1:1 grafting ratio. The design of the Y-shaped inimer includes both ATRP and NMP initiators attached to a common Y-junction. A copolymer of a Y-shaped inimer with glycidyl methacrylate is cross-linked to the substrate resulting in a stable ultrathin coating decorated with Y-shaped initiators. Weak PE A/B mixed brushes based on poly(methacrylic acid)/poly(2-vinylpyridine) (PMAA/P2VP) with a high grafting density of ∼1 chain/nm2 are grown by surface-initiated ATRP and NMP, respectively. Detailed morphological characterization of the PMAA/P2VP brushes in response to pH changes reveals a nanoporous morphology under conditions that maximize complex coacervate formation between oppositely charged brushes. The charge ratio between the A and B brushes is varied via the composition of the brushes to further study the morphology evolution. The effect of intimate contact between the A and B brushes on the morphology is probed by comparing with a mixed A/B PE system with random fluctuations in grafting composition. A quantitative and qualitative study of the pore evolution with pH as well as charge composition is presented using a combination of atomic force microscopy, water contact angle measurement, and image analysis using Gwyddion software. These studies demonstrate that the porous morphology is enhanced and most uniform when the brushes are grown from the Y-inimer, indicating that a 1:1 grafting ratio and intimate contact between A and B brushes are essential.
Collapse
Affiliation(s)
- Julia D Smith
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Ri Chen
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Nicolas Noriega Osores
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Padma Gopalan
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| |
Collapse
|
7
|
Nekoubin N, Sadeghi A, Chakraborty S. Highly Efficient Conversion of Salinity Difference to Electricity in Nanofluidic Channels Boosted by Variable Thickness Polyelectrolyte Coating. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:10171-10183. [PMID: 38698764 DOI: 10.1021/acs.langmuir.4c00477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
The inherent limits of the current produced by imposing salinity gradients along a nanofluidic channel having "hard" boundary walls heavily constrain the resulting energy harvesting efficacy, acting as major hindrances against the practicability of harnessing high power density from the mixing of water having different salinities. In this work, the infusion of variable-thickness polyelectrolyte layer of a conical shape is projected to augment salinity gradient power generation in nanochannels. Such a progressive thickening of a charged interfacial layer on account of axially declining ion concentration facilitates the shedding of enhanced numbers of mobile ions, bearing a net charge of equal and opposite to the surface-bound ions, into the mainstream current flow. We show that the proposed design can convert energy at a higher efficiency as compared to both solid-state and available polyelectrolyte layer (PEL)-covered nanochannels. The same is true for the maximum power density at moderate and high concentration ratios including natural salt gradient conditions for which more than 50% increase is achievable. The maximum values achieved for efficiency and power density read 50.3% and 6.6 kW/m2, respectively. Our results provide fundamental insights on strategizing variable-thickness polyelectrolyte layer grafting on the nanochannel interfaces, toward realizing high-performance osmotic power generators by altering the local ionic clouds alongside the grafted layers and enhancing the ionic mobility by inducing a driving potential gradient concomitantly. These findings open up a new strategy of efficient conversion of the power of the salinity difference of seawater and river water into electricity in a nanofluidic framework, surpassing the previously established limits of blue energy harvesting technologies.
Collapse
Affiliation(s)
- Nader Nekoubin
- Department of Mechanical Engineering, Amirkabir University of Technology, Tehran 15875-4413, Iran
| | - Arman Sadeghi
- Department of Mechanical Engineering, University of Kurdistan, Sanandaj 66177-15175, Iran
| | - Suman Chakraborty
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| |
Collapse
|
8
|
Smook LA, de Beer S. Electrical Chain Rearrangement: What Happens When Polymers in Brushes Have a Charge Gradient? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:4142-4151. [PMID: 38355408 PMCID: PMC10906002 DOI: 10.1021/acs.langmuir.3c03127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 02/16/2024]
Abstract
Under the influence of electric fields, the chains in polyelectrolyte brushes can stretch and collapse, which changes the structure of the brush. Copolymer brushes with charged and uncharged monomers display a similar behavior. For pure polyelectrolyte and random copolymer brushes, the field-induced structure changes only the density of the brush and not its local composition, while the latter could be affected if charges are distributed inhomogeneously along the polymer backbone. Therefore, we systematically study the switching behavior of gradient polyelectrolyte brushes in electric fields for different solvent qualities, grafting densities, and charges per chain via coarse-grained molecular dynamics simulations. Similar to random copolymers and pure polyelectrolytes, these brushes show a mixed-phase transition: intermediate states between fully stretched and collapsed are characterized by a bimodal chain-end distribution. Additionally, we find that the total charge of the brush plays a key role in the critical field required for a complete transition. Finally, we find that gradient polyelectrolyte brushes are charge-enriched at the brush-solvent interface under stretched conditions and charge-depleted under collapsed conditions, allowing for control over the local composition and thus the surface charge of the brush due to the inhomogeneous charge along the grafted chains.
Collapse
Affiliation(s)
- Leon A. Smook
- Department of Molecules and Materials,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Sissi de Beer
- Department of Molecules and Materials,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| |
Collapse
|
9
|
Hazra A, Samanta SK. Main-Chain Cationic Polyelectrolytes: Design, Synthesis, and Applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:2417-2438. [PMID: 38253020 DOI: 10.1021/acs.langmuir.3c02670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Polyelectrolytes have attracted a lot of attention spanning across disciplines, including polymer chemistry, materials chemistry, chemical biology, chemical engineering, as well as device physics, as a result of their widespread applications in sensing, biomedicine, food industry, wastewater treatment, optoelectronic devices, and renewable energy. In this review, we focus on the crucial synthetic strategies of structurally different classes of main-chain cationic polyelectrolytes. As a result of the presence of charged moieties in the main polymeric backbone, their solubility and photophysical properties can be easily tuned. Main-chain cationic polyelectrolytes provide various unique characteristics, including solubility in aqueous and organic solvents, easy processability, ease of film formation, ionic interaction, main-chain-directed charge transport, high conductivity, and aggregation. These properties make the main-chain polyelectrolyte a potential candidate for numerous applications ranging from chemo- and biosensing, antibacterial activity, optoelectronics, electrocatalysis, water splitting, ion conduction, to dye-sensitized solar cells.
Collapse
Affiliation(s)
- Amrita Hazra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Suman Kalyan Samanta
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| |
Collapse
|
10
|
Ishraaq R, Akash TS, Bera A, Das S. Hydrophilic and Apolar Hydration in Densely Grafted Cationic Brushes and Counterions with Large Mobilities. J Phys Chem B 2024; 128:381-392. [PMID: 38148252 DOI: 10.1021/acs.jpcb.3c07520] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
We employ an all-atom molecular dynamics (MD) simulation framework to unravel water microstructure and ion properties for cationic [poly(2-(methacryloyloxy)ethyl) trimethylammonium chloride] (PMETAC) brushes with chloride ions as counterions. First, we identify locally separate water domains (or first hydration shells) each around {N(CH3)3}+ and the C═O functional groups of the PMETAC chain and one around the Cl- ion. These first hydration shells around the respective moieties overlap, and the extent of the overlap depends on the nature of the species triggering it. Second, despite the overlap, the water molecules in these domains demonstrate disparate properties dictated by the properties of the atoms and groups around which they are located. For example, the presence of the methyl groups makes the {N(CH3)3}+ group trigger apolar hydration as evidenced by the corresponding orientation of the dipole of the water molecules around the {N(CH3)3}+ moiety. These water molecules around the {N(CH3)3}+ group also have enhanced tetrahedrality compared to the water molecules constituting the hydration layer around the C═O group and the Cl- counterion. Our simulations also identify that there is an intervening water layer between the Cl- ion and {N(CH3)3}+ group: this layer prevents the Cl- ion from coming very close to the {N(CH3)3}+ group. As a consequence, there is a significantly large mobility of the Cl- ions inside the PMETAC brush layer. Furthermore, the C═O group of the polyelectrolyte (PE) chain, due to the partial negative charge on the oxygen atom and the specific structure of the PMETAC brush system, demonstrates strongly hydrophilic behavior and enforces a specific dipole response of water molecules analogous to that experienced by water around anionic species of high charge density. In summary, our findings confirm that PMETAC brushes undergo hydrophilic hydration at one site and apolar hydration at another site and ensure large mobility of the supported Cl- counterions.
Collapse
Affiliation(s)
- Raashiq Ishraaq
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Tanmay Sarkar Akash
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Arka Bera
- 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
| |
Collapse
|
11
|
Yokokura TJ, Duan C, Ding EA, Kumar S, Wang R. Effects of Ionic Strength on the Morphology, Scattering, and Mechanical Response of Neurofilament-Derived Protein Brushes. Biomacromolecules 2024; 25:328-337. [PMID: 38052005 PMCID: PMC10872360 DOI: 10.1021/acs.biomac.3c01002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Protein brushes not only play a key role in the functionality of neurofilaments but also have wide applications in biomedical materials. Here, we investigate the effect of ionic strength on the morphology of protein brushes using continuous-space self-consistent field theory. A coarse-grained multiblock charged macromolecular model is developed to capture the chemical identity of amino acid sequences. For neurofilament heavy (NFH) brushes at pH 2.4, we predict three morphological regimes: swollen brushes, condensed brushes, and coexisting brushes, which consist of both a dense inner layer and a diffuse outer layer. The brush height predicted by our theory is in good agreement with the experimental data for a wide range of ionic strengths. The dramatic height decrease is a result of the electrostatic screening-induced transition from the overlapping state to the isolated state of the coexisting brushes. We also studied the evolution of the scattering and mechanical responses accompanying the morphological change. The oscillation in the reflectivity spectra characterizes the existence and microstructure of the inner condensed layer, whereas the shoulder in the force spectra signifies a swollen morphology.
Collapse
Affiliation(s)
- Takashi J Yokokura
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Chao Duan
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Erika A Ding
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Sanjay Kumar
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
- Department of Bioengineering, University of California, Berkeley, California 94720, United States
| | - Rui Wang
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
| |
Collapse
|
12
|
Al-Bataineh QM, Telfah AD, Shpacovitch V, Tavares CJ, Hergenröder R. Switchable Polyacrylic Acid Polyelectrolyte Brushes for Surface Plasmon Resonance Applications. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23094283. [PMID: 37177486 PMCID: PMC10181114 DOI: 10.3390/s23094283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/23/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Imaging wide-field surface plasmon resonance (SPR) microscopy sensors based on polyacrylic acid polyelectrolyte brushes (PAA PEBs) were designed to enhance the sensitivity of nano-object detection. The switching behavior of the PAA PEBs against changes in the pH values was investigated by analyzing the chemical, morphological, optical, and electrical properties. At pH ~1, the brushes collapse on the surface with the dominance of carboxylic groups (COOH). Upon the increase in the pH to nine, the switching process completes, and the brushes swell from dissociating most of the COOH groups and converting them into COO- groups. The domination of the negatively charged COO- groups increases the electrostatic repulsion in the polymer chains and stretches the brushes. The sensitivity of the SPR sensing device was investigated using a theoretical approach, as well as experimental measurements. The signal-to-noise ratio for a Au layer increases from six to eighteen after coating with PAA PEBs. In addition, the linewidth of the recorded image decreases from six pixels to five pixels by using the Au-PAA layers, which results from the enhanced spatial resolution of the recorded images. Coating a Au-layer with PAA PEBs enhances the sensitivity of the SPR sensing device, and improves the spatial resolution of the recorded image.
Collapse
Affiliation(s)
- Qais M Al-Bataineh
- Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany
- Experimental Physics, TU Dortmund University, 44227 Dortmund, Germany
| | - Ahmad D Telfah
- Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany
- Nanotechnology Center, The University of Jordan, Amman 11942, Jordan
| | - Victoria Shpacovitch
- Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany
| | - Carlos J Tavares
- Centre of Physics of Minho and Porto Universities, University of Minho, 4804-533 Guimarães, Portugal
| | - Roland Hergenröder
- Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany
| |
Collapse
|
13
|
Telles IM, Arfan M, Dos Santos AP. Effects of electrostatic coupling and surface polarization on polyelectrolyte brush structure. J Chem Phys 2023; 158:144902. [PMID: 37061472 DOI: 10.1063/5.0147056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023] Open
Abstract
In this work, we perform molecular dynamics simulations to study a spherical polyelectrolyte brush. We explore the effects of surface polarization and electrostatic coupling on brush size and distribution of counterions. The method of image charges is considered to take into account surface polarization, considering a metallic, an unpolarizable, and a dielectric nano-core. It is observed that, for all cases, a moderate shrinking-swelling effect appears with an increase in the electrostatic coupling parameter. This effect occurs under high Manning ratios. The curves relating the average size of polyelectrolyte brush as a function of coupling show a minimum. The results show that the grafting density of polyelectrolytes on the nano-core surface plays an important role in the polarization effect. We consider a modified Poisson-Boltzmann theory to describe the counterion profiles around the brush in the case of unpolarizable nano-cores and weak electrostatic coupling.
Collapse
Affiliation(s)
- Igor M Telles
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Muhammad Arfan
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Alexandre P Dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| |
Collapse
|
14
|
Qin J, Ziemann E, Bar-Zeev E, Bone SE, Liang Y, Mauter MS, Herzberg M, Bernstein R. Microporous Polyethersulfone Membranes Grafted with Zwitterionic Polymer Brushes Showing Microfiltration Permeance and Ultrafiltration Bacteriophage Removal. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18343-18353. [PMID: 37010122 DOI: 10.1021/acsami.3c01495] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Virus removal from water using microfiltration (MF) membranes is of great interest but remains challenging owing to the membranes' mean pore sizes typically being significantly larger than most viruses. We present microporous membranes grafted with polyzwitterionic brushes (N-dimethylammonium betaine) that combine bacteriophage removal in the range of ultrafiltration (UF) membranes with the permeance of MF membranes. Brush structures were grafted in two steps: free-radical polymerization followed by atom transfer radical polymerization (ATRP). Attenuated total reflection Fourier transform infrared (ATR-FTIR) and X-ray photoelectron (XPS) verified that grafting occurred at both sides of the membranes and that the grafting increased with increasing the zwitterion monomer concentration. The log reduction values (LRVs) of the pristine membrane increased from less than 0.5 LRV for T4 (∼100 nm) and NT1 (∼50 nm) bacteriophages to up to 4.5 LRV for the T4 and 3.1 LRV for the NT1 for the brush-grafted membranes with a permeance of about 1000 LMH/bar. The high permeance was attributed to a high-water fraction in the ultra-hydrophilic brush structure. The high measured LRVs of the brush-grafted membranes were attributed to enhanced bacteriophages exclusion from the membrane surface and entrapment of the ones that penetrated the pores due to the membranes' smaller mean pore-size and cross-section porosity than those of the pristine membrane, as seen by scanning electron microscopy (SEM) and measured using liquid-liquid porometry. Micro X-ray fluorescence (μ-XRF) spectrometry and nanoscale secondary ion mass spectrometry showed that 100 nm Si-coated gold nanospheres accumulated on the surface of the pristine membrane but not on the brush-coated membrane and that the nanospheres that penetrated the membranes were entrapped in the brush-grafted membrane but passed the pristine one. These results corroborate the LRVs obtained during filtration experiments and support the inference that the increased removal was due to a combined exclusion mechanism and entrapment. Overall, these microporous brush-grafted membranes show potential for use in advanced water treatment.
Collapse
Affiliation(s)
- Ji Qin
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research of the Ben-Gurion University of the Negev, Campus Sde Boker, Midreshet 84990, Israel
| | - Eric Ziemann
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research of the Ben-Gurion University of the Negev, Campus Sde Boker, Midreshet 84990, Israel
| | - Edo Bar-Zeev
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research of the Ben-Gurion University of the Negev, Campus Sde Boker, Midreshet 84990, Israel
| | - Sharon E Bone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Yuanzhe Liang
- Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
| | - Meagan S Mauter
- Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
| | - Moshe Herzberg
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research of the Ben-Gurion University of the Negev, Campus Sde Boker, Midreshet 84990, Israel
| | - Roy Bernstein
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research of the Ben-Gurion University of the Negev, Campus Sde Boker, Midreshet 84990, Israel
| |
Collapse
|
15
|
Yang X, Qi HK, Yang QH, Wang C, Luo MB. Height-Switching Dynamics of Mixed Polymer Brushes with Polymers of Different Stiffnesses. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4847-4854. [PMID: 36944145 DOI: 10.1021/acs.langmuir.3c00411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Mixed brushes consisting of flexible and semiflexible polymers of the same chain length exhibit a height-switching phenomenon because of rigidity-dependent critical adsorption [Yang et al. Macromolecules 2020, 53, 7369]. Semiflexible polymers stand higher at weak surface attraction (high temperature), but they close to the attractive surface at strong attraction (low temperature). In this work, the height-switching dynamics of the mixed polymer brushes is studied by Metropolis Monte Carlo simulation. The height-switching time is calculated by a sudden change in the surface attraction. Two surface attraction change modes, i.e., the weak-to-strong mode where the attraction is changed from weak to strong and the strong-to-weak mode where it is changed from strong to weak, are investigated. Simulation results show that the height-switching time is related to the grafting density, the polymer stiffness, and surface attraction change mode. We find that the height-switching time is significantly decreased for the strong-to-weak mode. And our results also show that the height switching in the mixed polymer brushes is reversible.
Collapse
Affiliation(s)
- Xiao Yang
- Department of Physics, Taizhou University, Taizhou, Zhejiang 318000, China
| | - Hang-Kai Qi
- Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Qing-Hui Yang
- Department of Physics, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Chao Wang
- Department of Physics, Taizhou University, Taizhou, Zhejiang 318000, China
| | - Meng-Bo Luo
- Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
| |
Collapse
|
16
|
Duan M, Chen G. Swelling and shrinking of two opposing polyelectrolyte brushes. Phys Rev E 2023; 107:024502. [PMID: 36932574 DOI: 10.1103/physreve.107.024502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 01/18/2023] [Indexed: 02/12/2023]
Abstract
Salt concentration and confinement effects affect the configuration of polyelectrolyte (PE) brushes due to electrostatic interactions. In this work, we develop a new theoretical model to analyze the electrostatics and swelling-shrinking behavior of two opposing PE brushes. By comparing three length scales, i.e., equilibrium brush height, separation distance, and Debye length, we obtain distinct scaling laws for brush height in different regimes. We provide explanations for the anomalous shrinkage of the PE brush with added salt reported in experiments and simulations, the applicability of the homogeneous brush assumption, and the confinement effect on the brush height. Our model can be used to shed light on the configuration and functionalities of PE-grafted interfaces, which play important roles in ion selective membranes and organism lubrication. We also anticipate that our method will be useful to understand the functionalities of other charged soft matter systems, such as hydrogel swelling and colloidal stability.
Collapse
Affiliation(s)
- Mingyu Duan
- Department of Advanced Manufacturing and Robotics, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Guang Chen
- Department of Advanced Manufacturing and Robotics, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| |
Collapse
|
17
|
Polymer brushes for friction control: Contributions of molecular simulations. Biointerphases 2023; 18:010801. [PMID: 36653299 DOI: 10.1116/6.0002310] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
When polymer chains are grafted to solid surfaces at sufficiently high density, they form brushes that can modify the surface properties. In particular, polymer brushes are increasingly being used to reduce friction in water-lubricated systems close to the very low levels found in natural systems, such as synovial joints. New types of polymer brush are continually being developed to improve with lower friction and adhesion, as well as higher load-bearing capacities. To complement experimental studies, molecular simulations are increasingly being used to help to understand how polymer brushes reduce friction. In this paper, we review how molecular simulations of polymer brush friction have progressed from very simple coarse-grained models toward more detailed models that can capture the effects of brush topology and chemistry as well as electrostatic interactions for polyelectrolyte brushes. We pay particular attention to studies that have attempted to match experimental friction data of polymer brush bilayers to results obtained using molecular simulations. We also critically look at the remaining challenges and key limitations to overcome and propose future modifications that could potentially improve agreement with experimental studies, thus enabling molecular simulations to be used predictively to modify the brush structure for optimal friction reduction.
Collapse
|
18
|
Pial TH, Das S. Specific Ion and Electric Field Controlled Diverse Ion Distribution and Electroosmotic Transport in a Polyelectrolyte Brush Grafted Nanochannel. J Phys Chem B 2022; 126:10543-10553. [PMID: 36454705 DOI: 10.1021/acs.jpcb.2c05524] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Controlling ion distribution inside a charged nanochannel is central to using such channels in diverse applications. Here, we show the possibility of using a charged polyelectrolyte (PE) brush-grafted nanochannel for triggering diverse nanoscopic ion distribution and nanofluidic electroosmotic transport by controlling the valence and size of the counterions (that screen the charges of the PE brushes) and the strength of an externally applied axial electric field. We atomistically simulate separate cases of fully charged polyacrylic acid (PAA) brush functionalized nanochannels with Na+, Cs+, Ca2+, Ba2+, and Y3+ counterions screening the PE charges. Four key findings emerge from our simulations. First, we find that the counterions with a greater valence and a smaller size prefer to remain localized inside the brush layer. Second, for the case where there is an added chloride salt with the same cation (as the screening counterions), there are more coions (Cl- ions) in the brush-free bulk than counterions (for counterions Na+, Ca2+, Ba2+, Y3+): this is a manifestation of the overscreening (OS) of the PE brush layer. Contrastingly, the number of Cs+ ions remain higher than the Cl- ions inside the brush-free bulk, ensuring that there is no OS effect for this case. Third, large applied electric field enables a few Na+, Cs+, and Ba2+ counterions to leave the brush layer and to go to the bulk: this makes the OS of the PE brush layer disappear for the cases of PE brushes being screened by the Na+ and Ba2+ ions. On the other hand, no such electric-field-mediated disappearance of OS is observed for the cases of Ca2+ and Y3+ screening counterions; we attribute this to the firm attachment of these counterions to the negatively charged monomers. Free energy associated with a counterion binding to a PE chain corroborates this diversity in the counterion-specific response to the applied electric field. Finally, we demonstrate that such diverse ion distributions, along with specific electric-field-strength-dependent ion properties, lead to (1) electroosmotic (EOS) transport in nanochannels grafted with PAA brushes screened with Cs+ ions to be always counterion dominated, (2) EOS transport in nanochannels grafted with PAA brushes screened with Ca2+ and Y3+ ions to be always coion-dominated, and (3) EOS transport in nanochannels grafted with PAA brushes screened with Na+ and Ba2+ ions to be coion dominated for smaller electric fields and counterion dominated for larger electric fields.
Collapse
Affiliation(s)
- Turash Haque Pial
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland20742, United States
| | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland20742, United States
| |
Collapse
|
19
|
Pial TH, Das S. Machine learning enabled quantification of the hydrogen bonds inside the polyelectrolyte brush layer probed using all-atom molecular dynamics simulations. SOFT MATTER 2022; 18:8945-8951. [PMID: 36421980 DOI: 10.1039/d2sm00997h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The configuration of densely grafted charged polyelectrolyte (PE) brushes is strongly dictated by the properties and behavior of the counterions that screen the PE brush charges and the solvent molecules (typically water) that solvate the brush molecules and these screening counterions. Only recently, efforts have been made to study the PE brushes atomistically, thereby shedding light on the properties of brush-supported ions and water molecules. However, even for such efforts, there are limitations associated with using a generic definition to estimate certain properties of water and ions inside the brush layer. For example, water-water hydrogen bonds (HBs) will behave differently for locations outside and inside the brush layer, given the fact that the densely closely grafted PE brush molecules create a soft nanoconfinement where the water connectivity becomes highly disrupted: therefore, using the same definition to quantify the HBs inside and outside the brush layer will be unwise. In this paper, we address this limitation by employing an unsupervised machine learning (ML) approach to predict the water-water hydrogen bonding inside a cationic PE brush layer modeled using all-atom molecular dynamics (MD) simulations. The ML method, which relies on a clustering approach and uses the equilibrium coordinates of the water molecules (obtained from the all-atom MD simulations) as the input, is capable of identifying the structural modification of water-water HBs (revealed through appropriate clustering of the data) inside the PE brush layer induced soft nanoconfinement. Such capabilities would not have been possible by using a generic definition of the HBs. Our calculations lead to four key findings: (1) the clusters formed inside and outside the brush layer are structurally similar; (2) the margin of the cluster is shorter inside the PE brush layer confirming the possible disruption of the HBs inside the PE brush layer; (3) the average "hydrogen-acceptor-oxygen-donor-oxygen" angle that defines the HB is reduced for the HBs formed inside the brush layer; (4) the use of the generic definition (definition usable for characterizing the HBs in brush-free bulk) leads to an overprediction of the number of HBs formed inside the PE brush layer.
Collapse
Affiliation(s)
- Turash Haque Pial
- 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.
| |
Collapse
|
20
|
Guo Y, Li L, Yang J. Intrachain and interchain complexation of polyacrylic acids bottlebrush chains with Ca2+ in aqueous solutions. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
21
|
Al‐Bataineh QM, Telfah AD, Ahmad AA, Bani‐Salameh AA, Abu‐Zurayk R, Hergenröder R. E
/
Z
reversible photoisomerization of methyl orange doped polyacrylic acid‐based polyelectrolyte brush films. J Appl Polym Sci 2022. [DOI: 10.1002/app.53138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Qais M. Al‐Bataineh
- Leibniz Institut für Analytische Wissenschaften‐ISAS‐e.V. Dortmund Germany
- Experimental Physics TU Dortmund University Dortmund Germany
- Department of Physics Jordan University of Science & Technology Irbid Jordan
| | - Ahmad D. Telfah
- Leibniz Institut für Analytische Wissenschaften‐ISAS‐e.V. Dortmund Germany
- Nanotechnology Center The University of Jordan Amman Jordan
| | - Ahmad A. Ahmad
- Department of Physics Jordan University of Science & Technology Irbid Jordan
| | | | - Rund Abu‐Zurayk
- Nanotechnology Center – The University of Jordan Amman Jordan
- Nanotechnology Center The University of Jordan Amman Jordan
| | - Roland Hergenröder
- Leibniz Institut für Analytische Wissenschaften‐ISAS‐e.V. Dortmund Germany
| |
Collapse
|
22
|
Iyer BVS. Effect of functional anisotropy on the local dynamics of polymer grafted nanoparticles. SOFT MATTER 2022; 18:6209-6221. [PMID: 35894123 DOI: 10.1039/d2sm00710j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
End-functionalised polymer grafted nanoparticles (PGNs) form bonds when their coronas overlap. The bonded interactions between the overlapping PGNs depend on the energy of the bonds (U). In the present study, oscillatory deformation imposed on a simple system with interacting PGNs placed on the vertices of a triangle is employed to examine the local dynamics as a function of energy of the bonds and the frequency of oscillation relative to the characteristic rupture frequency, ω0 = 2πν exp(-U/kBT), of the bonds. In particular, the effect of functional anisotropy is studied by introducing bonds of two different energies between adjacent PGNs. A multicomponent model developed by Kadre and Iyer, Macromol. Theory Simul., 2021, 30, 2100005, that combines the features of effective interactions between PGNs, self-consistent field theory and master equation approach to study bond kinetics is employed to obtain the local dynamics. The resulting force-strain curves are found to exhibit a simple broken symmetry where Fx (γ,) ≠ -Fx (-γ,-) and Fy (γ,) ≠ Fy (-γ,-) in systems with functional anisotropy. Fourier analysis of the dynamic response reveals that functional anisotropy leads to finite even harmonic terms and systematic variation of both the elastic and dissipative response from that of the isotropic systems. Furthermore, the intra-cycle variations in the strain stiffening and shear thickening ratios obtained from the analysis indicate that functional anisotropy leads to anisotropic nonlinear response.
Collapse
Affiliation(s)
- Balaji V S Iyer
- Department of Chemical Engineering, IIT Hyderabad, Hyderabad, India.
| |
Collapse
|
23
|
Aktas Eken G, Ober CK. Strong Polyelectrolyte Brushes via Alternating Copolymers of Styrene and Maleimides: Synthesis, Properties, and Stability. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00647] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Gozde Aktas Eken
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Christopher K. Ober
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| |
Collapse
|
24
|
Zimmermann R, Duval JF, Werner C, Sterling JD. Quantitative insights into electrostatics and structure of polymer brushes from microslit electrokinetic experiments and advanced modelling of interfacial electrohydrodynamics. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
25
|
Nanostructured Materials for Water Purification: Adsorption of Heavy Metal Ions and Organic Dyes. Polymers (Basel) 2022; 14:polym14112183. [PMID: 35683856 PMCID: PMC9182857 DOI: 10.3390/polym14112183] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 12/19/2022] Open
Abstract
Chemical water pollution poses a threat to human beings and ecological systems. The purification of water to remove toxic organic and inorganic pollutants is essential for a safe society and a clean environment. Adsorption-based water treatment is considered one of the most effective and economic technologies designed to remove toxic substances. In this article, we review the recent progress in the field of nanostructured materials used for water purification, particularly those used for the adsorption of heavy metal ions and organic dyes. This review includes a range of nanostructured materials such as metal-based nanoparticles, polymer-based nanomaterials, carbon nanomaterials, bio-mass materials, and other types of nanostructured materials. Finally, the current challenges in the fields of adsorption of toxic materials using nanostructured materials are briefly discussed.
Collapse
|
26
|
Ritsema van Eck G, Chiappisi L, de Beer S. Fundamentals and Applications of Polymer Brushes in Air. ACS APPLIED POLYMER MATERIALS 2022; 4:3062-3087. [PMID: 35601464 PMCID: PMC9112284 DOI: 10.1021/acsapm.1c01615] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/03/2022] [Indexed: 05/22/2023]
Abstract
For several decades, high-density, end-tethered polymers, forming so-called polymer brushes, have inspired scientists to understand their properties and to translate them to applications. While earlier research focused on polymer brushes in liquids, it was recently recognized that these brushes can find application in air as well. In this review, we report on recent progress in unraveling fundamental concepts of brushes in air, such as their vapor-swelling and solvent partitioning. Moreover, we provide an overview of the plethora of applications in air (e.g., in sensing, separations or smart adhesives) where brushes can be key components. To conclude, we provide an outlook by identifying open questions and issues that, when solved, will pave the way for the large scale application of brushes in air.
Collapse
Affiliation(s)
- Guido
C. Ritsema van Eck
- Sustainable
Polymer Chemistry Group, Department of Molecules & Materials,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Leonardo Chiappisi
- Institut
Max von Laue - Paul Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Sissi de Beer
- Sustainable
Polymer Chemistry Group, Department of Molecules & Materials,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| |
Collapse
|
27
|
Li S, Shi X. 接枝高分子对纳米-生物界面粘附性能的调控研究进展. CHINESE SCIENCE BULLETIN-CHINESE 2022. [DOI: 10.1360/tb-2022-0449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
28
|
Romero-Sanchez I, Pihlajamaa I, Adžić N, Castellano LE, Stiakakis E, Likos CN, Laurati M. Blunt-End Driven Re-entrant Ordering in Quasi Two-Dimensional Dispersions of Spherical DNA Brushes. ACS NANO 2022; 16:2133-2146. [PMID: 35130432 PMCID: PMC8867906 DOI: 10.1021/acsnano.1c07799] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We investigate the effects of crowding on the conformations and assembly of confined, highly charged, and thick polyelectrolyte brushes in the osmotic regime. Particle tracking experiments on increasingly dense suspensions of colloids coated with ultralong double-stranded DNA (dsDNA) fragments reveal nonmonotonic particle shrinking, aggregation, and re-entrant ordering. Theory and simulations show that aggregation and re-entrant ordering arise from the combined effect of shrinking, which is induced by the osmotic pressure exerted by the counterions absorbed in neighbor brushes and of a short-range attractive interaction competing with electrostatic repulsion. An unconventional mechanism gives origin to the short-range attraction: blunt-end interactions between stretched dsDNA fragments of neighboring brushes, which become sufficiently intense for dense and packed brushes. The attraction can be tuned by inducing free-end backfolding through the addition of monovalent salt. Our results show that base stacking is a mode parallel to hybridization to steer colloidal assembly in which attractions can be fine-tuned through salinity and, potentially, grafting density and temperature.
Collapse
Affiliation(s)
- Ivany Romero-Sanchez
- Dipartimento
di Chimica & CSGI, Università
di Firenze, 50019 Sesto Fiorentino, Italy
- División
de Ciencias e Ingenierías, Universidad
de Guanajuato, 37150 León, Mexico
| | - Ilian Pihlajamaa
- Faculty
of Physics, University of Vienna, Bolzmanngasse 5, A-1090 Vienna, Austria
- Eindhoven
University of Technology, Department of
Applied Physics, Soft Matter and Biological Physics, Postbus 513, NL-5600 MB Eindhoven, The Netherlands
| | - Natasa Adžić
- Faculty
of Physics, University of Vienna, Bolzmanngasse 5, A-1090 Vienna, Austria
| | - Laura E. Castellano
- División
de Ciencias e Ingenierías, Universidad
de Guanajuato, 37150 León, Mexico
| | - Emmanuel Stiakakis
- Biomacromolecular
Systems and Processes, Institute of Biological Information Processing
(IBI-4), 4 Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Christos N. Likos
- Faculty
of Physics, University of Vienna, Bolzmanngasse 5, A-1090 Vienna, Austria
| | - Marco Laurati
- Dipartimento
di Chimica & CSGI, Università
di Firenze, 50019 Sesto Fiorentino, Italy
| |
Collapse
|
29
|
Wu P, Sun T, Jiang X. Non-monotonic variation of flow strength in nanochannels grafted with end-charged polyelectrolyte layers. RSC Adv 2022; 12:4061-4071. [PMID: 35425443 PMCID: PMC8981053 DOI: 10.1039/d1ra06601c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/25/2021] [Indexed: 11/30/2022] Open
Abstract
The electrokinetic transport of fluids, also called the electroosmotic flow (EOF), in micro/nanoscale devices occurs in promising applications such as electrokinetic energy conversion (EKEC) systems. Recently, EKEC systems grafted with end-charged polyelectrolyte (PE) layers (PELs) have been reported to exhibit higher efficiencies than those of intrinsic systems. Understanding the interplay between the end-charged PELs and electrical double layers (EDLs) on the EOF is crucial for designing highly efficient EKEC systems. The interplay between the end-charged PELs and EDLs on the strength of the EOF (V0) is studied by explicitly modeling the EOF through nanochannels grafted with end-charged PELs using atomic simulations. The variation of V0 is examined for nanochannels grafted with PELs at various separations (d = 3.5–0.4 nm) to cover various conformations of PEs, inlcuding mushroom, semi-dilute brushes, and concentrated brushes. We find that V0 follows a non-monotonic variation as d decreases and this is correlated with the conformation of the PEs. Specifically, as d decreases, V0 decreases first in the mushroom regime (d = 3.5–2.0 nm), and then V0 increases in the concentrated brush regime (d = 0.75–0.4 nm). Navigated by the continuum Navier–Stokes–Brinkman model, the above observations are rationalized by the competition between the driving effect from the spatial shift of ions in EDLs and the drag effect from PELs. The insights obtained in this work are important to guide the design of highly efficient EKEC systems by grafting end-charged PELs onto channel surfaces. A non-monotonic variation of the strength of electroosmotic flow (V0) is reported for the electroosmotic flow through nanochannels grafted with end-charged polyelectrolytes at various separation using atomic simulations.![]()
Collapse
Affiliation(s)
- Peng Wu
- College of Energy and Power Engineering, Inner Mongolia University of Technology, Inner Mongolia, Hohhot, 010051, China
- China–EU Institute of Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Tao Sun
- China–EU Institute of Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Xikai Jiang
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China
| |
Collapse
|
30
|
Chun B, Chun MS. Electrostatic Potential Analysis in Polyelectrolyte Brush-Grafted Microchannels Filled with Polyelectrolyte Dispersion. MICROMACHINES 2021; 12:mi12121475. [PMID: 34945324 PMCID: PMC8706125 DOI: 10.3390/mi12121475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 11/25/2021] [Accepted: 11/28/2021] [Indexed: 11/24/2022]
Abstract
In this study, the model framework that includes almost all relevant parameters of interest has been developed to quantify the electrostatic potential and charge density occurring in microchannels grafted with polyelectrolyte brushes and simultaneously filled with polyelectrolyte dispersion. The brush layer is described by the Alexander-de Gennes model incorporated with the monomer distribution function accompanying the quadratic decay. Each ion concentration due to mobile charges in the bulk and fixed charges in the brush layer can be determined by multi-species ion balance. We solved 2-dimensional Poisson–Nernst–Planck equations adopted for simulating electric field with ion transport in the soft channel, by considering anionic polyelectrolyte of polyacrylic acid (PAA). Remarkable results were obtained regarding the brush height, ionization, electrostatic potential, and charge density profiles with conditions of brush, dispersion, and solution pH. The Donnan potential in the brush channel shows several times higher than the surface potential in the bare channel, whereas it becomes lower with increasing PAA concentration. Our framework is fruitful to provide comparative information regarding electrostatic interaction properties, serving as an important bridge between modeling and experiments, and is possible to couple with governing equations for flow field.
Collapse
Affiliation(s)
- Byoungjin Chun
- Complex Fluids Laboratory, Advanced Materials Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
- Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Korea
| | - Myung-Suk Chun
- Complex Fluids Laboratory, Advanced Materials Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
- Biomedical Engineering Department, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
| |
Collapse
|
31
|
Durmaz EN, Sahin S, Virga E, de Beer S, de Smet LCPM, de Vos WM. Polyelectrolytes as Building Blocks for Next-Generation Membranes with Advanced Functionalities. ACS APPLIED POLYMER MATERIALS 2021; 3:4347-4374. [PMID: 34541543 PMCID: PMC8438666 DOI: 10.1021/acsapm.1c00654] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/10/2021] [Indexed: 05/06/2023]
Abstract
The global society is in a transition, where dealing with climate change and water scarcity are important challenges. More efficient separations of chemical species are essential to reduce energy consumption and to provide more reliable access to clean water. Here, membranes with advanced functionalities that go beyond standard separation properties can play a key role. This includes relevant functionalities, such as stimuli-responsiveness, fouling control, stability, specific selectivity, sustainability, and antimicrobial activity. Polyelectrolytes and their complexes are an especially promising system to provide advanced membrane functionalities. Here, we have reviewed recent work where advanced membrane properties stem directly from the material properties provided by polyelectrolytes. This work highlights the versatility of polyelectrolyte-based membrane modifications, where polyelectrolytes are not only applied as single layers, including brushes, but also as more complex polyelectrolyte multilayers on both porous membrane supports and dense membranes. Moreover, free-standing membranes can also be produced completely from aqueous polyelectrolyte solutions allowing much more sustainable approaches to membrane fabrication. The Review demonstrates the promise that polyelectrolytes and their complexes hold for next-generation membranes with advanced properties, while it also provides a clear outlook on the future of this promising field.
Collapse
Affiliation(s)
- Elif Nur Durmaz
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, Enschede 7500 AE, The Netherlands
| | - Sevil Sahin
- Laboratory
of Organic Chemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Ettore Virga
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, Enschede 7500 AE, The Netherlands
- Wetsus, European
Centre of Excellence for Sustainable Water
Technology, Oostergoweg
9, 8911 MA Leeuwarden, The Netherlands
| | - Sissi de Beer
- Sustainable
Polymer Chemistry Group, Department of Molecules and Materials MESA+
Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Louis C. P. M. de Smet
- Laboratory
of Organic Chemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Wiebe M. de Vos
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, Enschede 7500 AE, The Netherlands
| |
Collapse
|
32
|
Luo Y, Wang C, Pang AP, Zhang X, Wang D, Lu X. Low-Concentration Salt Solution Changes the Interfacial Molecular Behavior of Polyelectrolyte Brushes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00119] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yongsheng Luo
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Chu Wang
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Ai-Ping Pang
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| | - Xiang Zhang
- National Center for International Joint Research of Micro−Nano Molding Technology, School of Mechanics & Engineering Science, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Dayang Wang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, Jilin Province, P. R. China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, Jiangsu Province, P. R. China
| |
Collapse
|
33
|
Wang L, Wang S, Tong C. The collapse of polyelectrolyte brushes made of 4-arm stars mediated by trivalent salt counterions. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1932875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Lijuan Wang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, People’s Republic of China
| | - Shaoyun Wang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, People’s Republic of China
| | - Chaohui Tong
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, People’s Republic of China
| |
Collapse
|
34
|
Ji Y, Wang SY, Tong CH. Collapse of four-arm stars polyelectrolyte brushes under an electric field in the presence of trivalent salt coions. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2004059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Yu Ji
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Shao-yun Wang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Chao-hui Tong
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| |
Collapse
|
35
|
Nicolas M, Beyou E, Fumagalli M. Two-step synthesis of polystyrene sulfonate based copolymers bearing pendant primary amines. Eur Polym J 2021. [DOI: 10.1016/j.eurpolymj.2021.110455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
36
|
Tolmachev D, Mamistvalov G, Lukasheva N, Larin S, Karttunen M. Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes. Polymers (Basel) 2021; 13:polym13111789. [PMID: 34071693 PMCID: PMC8199235 DOI: 10.3390/polym13111789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.
Collapse
Affiliation(s)
- Dmitry Tolmachev
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 Petersburg, Russia; (N.L.); (S.L.)
- Correspondence: (D.T.); (M.K.)
| | - George Mamistvalov
- Faculty of Physics, St. Petersburg State University, Petrodvorets, 198504 Petersburg, Russia;
| | - Natalia Lukasheva
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 Petersburg, Russia; (N.L.); (S.L.)
| | - Sergey Larin
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 Petersburg, Russia; (N.L.); (S.L.)
- Faculty of Physics, St. Petersburg State University, Petrodvorets, 198504 Petersburg, Russia;
| | - Mikko Karttunen
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 Petersburg, Russia; (N.L.); (S.L.)
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Department of Applied Mathematics, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- The Centre of Advanced Materials and Biomaterials Research, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Correspondence: (D.T.); (M.K.)
| |
Collapse
|
37
|
Pial TH, Sachar HS, Das S. Quantification of Mono- and Multivalent Counterion-Mediated Bridging in Polyelectrolyte Brushes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00328] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Turash Haque Pial
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Harnoor Singh Sachar
- 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
| |
Collapse
|
38
|
Silkina EF, Bag N, Vinogradova OI. Surface and zeta potentials of charged permeable nanocoatings. J Chem Phys 2021; 154:164701. [PMID: 33940807 DOI: 10.1063/5.0041350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
An electrokinetic (zeta) potential of charged permeable porous films on solid supports generally exceeds their surface potential, which often builds up to a quite high value itself. Recent work provided a quantitative understanding of zeta potentials of thick, compared to the extension of an inner electrostatic diffuse layer, porous films. Here, we consider porous coatings of thickness comparable to or smaller than that of the inner diffuse layer. Our theory, which is valid even when electrostatic potentials become quite high and accounts for finite hydrodynamic permeability of the porous materials, provides a framework for interpreting the difference between values of surface and zeta potentials in various situations. Analytic approximations for the zeta potential in the experimentally relevant limits provide a simple explanation of transitions between different regimes of electro-osmotic flows and also suggest strategies for its tuning in microfluidic applications.
Collapse
Affiliation(s)
- Elena F Silkina
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, 119071 Moscow, Russia
| | - Naren Bag
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056 Aachen, Germany
| | - Olga I Vinogradova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, 119071 Moscow, Russia
| |
Collapse
|
39
|
Pial TH, Sachar HS, Desai PR, Das S. Overscreening, Co-Ion-Dominated Electroosmosis, and Electric Field Strength Mediated Flow Reversal in Polyelectrolyte Brush Functionalized Nanochannels. ACS NANO 2021; 15:6507-6516. [PMID: 33797221 DOI: 10.1021/acsnano.0c09248] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Controlling the direction and strength of nanofluidic electrohydrodyanmic transport in the presence of an externally applied electric field is extremely important in a number of nanotechnological applications. Here, we employ all-atom molecular dynamics simulations to discover the possibility of changing the direction of electroosmotic (EOS) liquid flows by merely changing the electric field strength in a nanochannel functionalized with polyelectrolyte (PE) brushes. In exploring this, we have uncovered three facets of nanoconfined PE brush behavior and resulting EOS transport. First, we identify the onset of an overscreening effect: such overscreening refers to the presence of more counterions (Na+) within the brush layer than needed to neutralize the negative brush charges. Accordingly, as a consequence of the overscreening, in the bulk liquid outside the brush layer, there is a greater number of co-ions (Cl-) than counterions in the presence of an added salt (NaCl). Second, this specific ion distribution ensures that the overall EOS flow is along the direction of motion of the co-ions. Such co-ion-dictated EOS transport directly contradicts the notion that EOS flow is always dictated by the motion of the counterions. Finally, for large-enough electric fields, the brush height reduces significantly, causing some of the excess overscreening-inducing counterions to squeeze out of the PE brush layer into the brush-free bulk. As a result, the overscreening effect disappears and the number of co-ions and counterions outside the PE brush layer become similar. Despite that there is an EOS transport, this EOS transport, unlike the standard EOS transport that occurs due to the imbalance of the co-ions and counterions, occurs since a larger residence time of the water molecules in the first solvation shell of the counterions (Na+) ensures a water transport in the direction of motion of the counterions. The net effect is the reversal of the direction of the EOS transport by merely changing the strength of the electric field.
Collapse
Affiliation(s)
- Turash Haque Pial
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Harnoor Singh Sachar
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Parth Rakesh Desai
- 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
| |
Collapse
|
40
|
Bondaz L, Cousin F, Muller F, Pantoustier N, Perrin P, Luchini A, Goldmann M, Fontaine P. pH-sensitive behavior of the PS-b-PDMAEMA copolymer at the air - water interface. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123619] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
41
|
Li D, Xu L, Wang J, Gautrot JE. Responsive Polymer Brush Design and Emerging Applications for Nanotheranostics. Adv Healthc Mater 2021; 10:e2000953. [PMID: 32893474 DOI: 10.1002/adhm.202000953] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/11/2020] [Indexed: 12/29/2022]
Abstract
Responsive polymer brushes are a category of polymer brushes that are capable of conformational and chemical changes in response to external stimuli. They offer unique opportunities for the control of bio-nano interactions due to the precise control of chemical and structural parameters such as the brush thickness, density, chemistry, and architecture. The design of responsive brushes at the surface of nanomaterials for theranostic applications has developed rapidly. These coatings can be generated from a very broad range of nanomaterials, without compromising their physical, photophysical, and imaging properties. Although the use of responsive brushes for nanotheranostic remains in its early stages, in this review, the aim is to present how the systems developed to date can be combined to control sensing, imaging, and controlled delivery of therapeutics. The recent developments for such design and associated methods for the synthesis of responsive brushes are discussed. The responsive behaviors of homo polymer brushes and brushes with more complex architectures are briefly reviewed, before the applications of responsive brushes as smart delivery systems are discussed. Finally, the recent work is summarized on the use of responsive polymer brushes as novel biosensors and diagnostic tools for the detection of analytes and biomarkers.
Collapse
Affiliation(s)
- Danyang Li
- School of Cancer and Pharmaceutical Sciences King's College London 150 Stamford Street London SE1 9NH UK
- Institute of Bioengineering Queen Mary University of London Mile End Road London E1 4NS UK
- School of Engineering and Materials Science Queen Mary University of London Mile End Road London E1 4NS UK
| | - Lizhou Xu
- Department of Materials Imperial College London London SW7 2AZ UK
| | - Jing Wang
- School of Life Sciences Northwestern Polytechnical University Xi'an 710072 China
| | - Julien E. Gautrot
- Institute of Bioengineering Queen Mary University of London Mile End Road London E1 4NS UK
- School of Engineering and Materials Science Queen Mary University of London Mile End Road London E1 4NS UK
| |
Collapse
|
42
|
Photografting of biochelator onto polypropylene film as an antioxidant clean label. Food Chem 2021; 351:129362. [PMID: 33647698 DOI: 10.1016/j.foodchem.2021.129362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 02/10/2021] [Accepted: 02/10/2021] [Indexed: 11/19/2022]
Abstract
A ligand film with citric acid (CA) on the surface as a biochelator was prepared via photografting. Polypropylene film was photochemically brushed by immobilizing glycidyl methacrylate onto the film surface (PP-g-GMA) in the presence of benzophenone. The ligand film (PP-g-GMA-g-CA) was developed via a ring-opening reaction between PP-g-GMA and CA. The chemical structure was examined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Microstructure and grafting morphology were observed using scanning electron microscopy and atomic force microscopy, and brushed-like configuration and porous surface morphology were described. A large amount of carboxylic acid (215 ± 11 nm) was detected on the surface of PP-g-GMA-g-CA and afforded chelation of Fe3+ (215 ± 11 nm). This ligand film exhibited chelating activity in vitamin C and virgin olive oil (p < 0.05), which extended the shelf-life of these foods. Moreover, overall migration analysis demonstrated that it can be considered as a non-migratory antioxidant.
Collapse
|
43
|
Photografting of conducting polymer onto polymeric substrate as non-migratory antioxidant packaging. REACT FUNCT POLYM 2021. [DOI: 10.1016/j.reactfunctpolym.2020.104792] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
44
|
Thankappan H, Semsarilar M, Li S, Chang Y, Bouyer D, Quemener D. Synthesis of Block Copolymer Brush by RAFT and Click Chemistry and Its Self-Assembly as a Thin Film. MOLECULES (BASEL, SWITZERLAND) 2020; 25:molecules25204774. [PMID: 33080832 PMCID: PMC7587578 DOI: 10.3390/molecules25204774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 11/16/2022]
Abstract
A well-defined block copolymer brush poly(glycidyl methacrylate)-graft-(poly(methyl methacrylate)-block- poly(oligo(ethylene glycol) methyl ether methacrylate)) (PGMA-g-(PMMA-b-POEGMA)) is synthesized via grafting from an approach based on a combination of click chemistry and reversible addition-fragmentation chain transfer (RAFT) polymerization. The resulting block copolymer brushes were characterized by 1H-NMR and size exclusion chromatography (SEC). The self-assembly of the block copolymer brush was then investigated under selective solvent conditions in three systems: THF/water, THF/CH3OH, and DMSO/CHCl3. PGMA-g-(PMMA-b-POEGMA) was found to self-assemble into spherical micelle structures as analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The average size of the particles was much smaller in THF/CH3OH and DMSO/CHCl3 as compared with the THF/water system. Thin film of block copolymer brushes with tunable surface properties was then prepared by the spin-coating technique. The thickness of the thin film was confirmed by scanning electron microscopy (SEM). Atom force microscopy (AFM) analysis revealed a spherical morphology when the block copolymer brush was treated with poor solvents for the backbone and hydrophobic side chains. The contact angle measurements were used to confirm the surface rearrangements of the block copolymer brushes.
Collapse
Affiliation(s)
- Hajeeth Thankappan
- Institut Européen des Membranes, IEM-UMR 5635, Univ Montpellier, ENSCM, CNRS, 34095 Montpellier, France; (H.T.); (M.S.); (S.L.); (D.B.)
| | - Mona Semsarilar
- Institut Européen des Membranes, IEM-UMR 5635, Univ Montpellier, ENSCM, CNRS, 34095 Montpellier, France; (H.T.); (M.S.); (S.L.); (D.B.)
| | - Suming Li
- Institut Européen des Membranes, IEM-UMR 5635, Univ Montpellier, ENSCM, CNRS, 34095 Montpellier, France; (H.T.); (M.S.); (S.L.); (D.B.)
| | - Yung Chang
- Department of Chemical Engineering, R&D Center for Membrane Technology, Chung Yuan Christian University, 200, Chung-Bei Rd., Chungli, Taoyuan, 320, Taiwan;
| | - Denis Bouyer
- Institut Européen des Membranes, IEM-UMR 5635, Univ Montpellier, ENSCM, CNRS, 34095 Montpellier, France; (H.T.); (M.S.); (S.L.); (D.B.)
| | - Damien Quemener
- Institut Européen des Membranes, IEM-UMR 5635, Univ Montpellier, ENSCM, CNRS, 34095 Montpellier, France; (H.T.); (M.S.); (S.L.); (D.B.)
- Correspondence:
| |
Collapse
|
45
|
Yang X, Huang JH, Mikhailov IV, Polotsky AA, Luo MB. Height Switching in Mixed Polymer Brushes with Polymers of Different Stiffnesses. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Xiao Yang
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jian-Hua Huang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Ivan V. Mikhailov
- Institute of Macromolecular Compounds, Russian Academy of Sciences, 31 Bolshoy pr, 199004 Saint Petersburg, Russia
| | - Alexey A. Polotsky
- Institute of Macromolecular Compounds, Russian Academy of Sciences, 31 Bolshoy pr, 199004 Saint Petersburg, Russia
| | - Meng-Bo Luo
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| |
Collapse
|
46
|
Wang T, Wang S, Tong C. Charge reversal in the collapse of polyelectrolyte star brushes under an electric field. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
47
|
Zhou LY, Zhu YH, Wang XY, Shen C, Wei XW, Xu T, He ZY. Novel zwitterionic vectors: Multi-functional delivery systems for therapeutic genes and drugs. Comput Struct Biotechnol J 2020; 18:1980-1999. [PMID: 32802271 PMCID: PMC7403891 DOI: 10.1016/j.csbj.2020.07.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/17/2020] [Accepted: 07/18/2020] [Indexed: 02/05/2023] Open
Abstract
Zwitterions consist of equal molar cationic and anionic moieties and thus exhibit overall electroneutrality. Zwitterionic materials include phosphorylcholine, sulfobetaine, carboxybetaine, zwitterionic amino acids/peptides, and other mix-charged zwitterions that could form dense and stable hydration shells through the strong ion-dipole interaction among water molecules and zwitterions. As a result of their remarkable hydration capability and low interfacial energy, zwitterionic materials have become ideal choices for designing therapeutic vectors to prevent undesired biosorption especially nonspecific biomacromolecules during circulation, which was termed antifouling capability. And along with their great biocompatibility, low cytotoxicity, negligible immunogenicity, systematic stability and long circulation time, zwitterionic materials have been widely utilized for the delivery of drugs and therapeutic genes. In this review, we first summarized the possible antifouling mechanism of zwitterions briefly, and separately introduced the features and advantages of each type of zwitterionic materials. Then we highlighted their applications in stimuli-responsive "intelligent" drug delivery systems as well as tumor-targeting carriers and stressed the multifunctional role they played in therapeutic gene delivery.
Collapse
Affiliation(s)
- Ling-Yan Zhou
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan 610041, China
| | - Yang-Hui Zhu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan 610041, China
| | - Xiao-Yu Wang
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan 610041, China
| | - Chao Shen
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan 610041, China
| | - Xia-Wei Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041 Sichuan, China
| | - Ting Xu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan 610041, China
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041, China
| | - Zhi-Yao He
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan 610041, China
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041, China
| |
Collapse
|
48
|
Wiedmann S, Kerscher B, Lienert C, Böcherer D, Mülhaupt R. Tailoring Poly(2-oxazoline)-Based Polymeric Ionic Liquids as Thermoresponsive Molecular Brushes and Programmable Dispersants for Silver Nanoparticles. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00267] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Steffen Wiedmann
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
- Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Str. 21, D-79104 Freiburg, Germany
- Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, Georges-Köhler-Allee 105, D-79110 Freiburg, Germany
| | - Benjamin Kerscher
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
- Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Str. 21, D-79104 Freiburg, Germany
| | - Caroline Lienert
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
| | - David Böcherer
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
| | - Rolf Mülhaupt
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
- Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Str. 21, D-79104 Freiburg, Germany
- Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, Georges-Köhler-Allee 105, D-79110 Freiburg, Germany
| |
Collapse
|
49
|
Gaikwad HS, Kumar G, Mondal PK. Efficient electroosmotic mixing in a narrow-fluidic channel: the role of a patterned soft layer. SOFT MATTER 2020; 16:6304-6316. [PMID: 32572423 DOI: 10.1039/d0sm00890g] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We propose a novel and efficient mixing technique in a soft narrow-fluidic channel under the influence of electrical forcing. We show that a grafted polyelectrolyte layer (PEL) added as a patch to the channel wall modulates the electrical double layer (EDL) so that an applied electric field initiates a local electroosmotic flow (EOF) at the patched section. This EOF develops in the opposite direction to the primary pressure-driven flow. This localized EOF leads to the formation of Lamb vortices at the patched sections through the phenomenon of momentum exchange with the primary stream and promotes the mixing therein. Our study, consistent with the stream-function/vorticity approach, primarily focuses on the numerical analysis of the mixing phenomena. Through a quantitative description, we reveal the effect of different patterns on the underlying mixing phenomena in the convective mixing regime. We also discuss the impact of key parameters on the mixing efficiency, the onset of the recirculation zone, variation in the mixing length, and the shear-driven aggregation kinetics in soft matter systems. Finally, considering the practicability of the present problem, we unveil the values of several design parameters for which the mixing efficiency in the channel reaches the maximum.
Collapse
Affiliation(s)
- Harshad Sanjay Gaikwad
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India.
| | | | | |
Collapse
|
50
|
Horkay F, Chremos A, Douglas JF, L. Jones R, Lou J, Xia Y. Systematic investigation of synthetic polyelectrolyte bottlebrush solutions by neutron and dynamic light scattering, osmometry, and molecular dynamics simulation. J Chem Phys 2020; 152:194904. [PMID: 33687251 PMCID: PMC7252672 DOI: 10.1063/5.0007271] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/03/2020] [Indexed: 01/30/2023] Open
Abstract
There is a great interest in the synthesis and characterization of polyelectrolytes that mimic naturally occurring bottlebrush polyelectrolytes to capitalize on the unique properties of this class of macromolecules. Charged bottlebrush polymers form the protective mucus layer in the lungs, stomach, and orifices of animals and provide osmotic stabilization and lubrication to joints. In the present work, we systematically investigate bottlebrush poly(sodium acrylates) through a combination of measurements of solution properties (osmometry, small-angle neutron scattering, and dynamic light scattering) and molecular dynamics simulations, where the bottlebrush properties are compared in each case to their linear polymer counterparts. These complementary experimental and computational methods probe vastly different length- and timescales, allowing for a comprehensive characterization of the supermolecular structure and dynamics of synthetic polyelectrolyte bottlebrush molecules in solution.
Collapse
Affiliation(s)
- Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Alexandros Chremos
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Ronald L. Jones
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Junzhe Lou
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Yan Xia
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| |
Collapse
|