scholarly journals Modeling of emergent memory and voltage spiking in ionic transport through angstrom-scale slits

Science ◽  
2021 ◽  
Vol 373 (6555) ◽  
pp. 687-691 ◽  
Author(s):  
Paul Robin ◽  
Nikita Kavokine ◽  
Lydéric Bocquet
Keyword(s):  
Ion Transport ◽  
Molecular Layer ◽  
Nonlinear Effects ◽  
Ionic Transport ◽  
Ion Dynamics ◽  
Proof Of Concept ◽  
Molecular Control ◽  
Strongly Nonlinear ◽  
Dynamics Simulations ◽  
Single Molecular Layer

Recent advances in nanofluidics have enabled the confinement of water down to a single molecular layer. Such monolayer electrolytes show promise in achieving bioinspired functionalities through molecular control of ion transport. However, the understanding of ion dynamics in these systems is still scarce. Here, we develop an analytical theory, backed up by molecular dynamics simulations, that predicts strongly nonlinear effects in ion transport across quasi–two-dimensional slits. We show that under an electric field, ions assemble into elongated clusters, whose slow dynamics result in hysteretic conduction. This phenomenon, known as the memristor effect, can be harnessed to build an elementary neuron. As a proof of concept, we carry out molecular simulations of two nanofluidic slits that reproduce the Hodgkin-Huxley model and observe spontaneous emission of voltage spikes characteristic of neuromorphic activity.

scholarly journals Characterization of design grammar of peptides for regulating liquid droplets and aggregates of FUS

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kiyoto Kamagata ◽  
Rika Chiba ◽  
Ichiro Kawahata ◽  
Nanako Iwaki ◽  
Saori Kanbayashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Electrostatic Interactions ◽  
Amyloid Fibrils ◽  
Droplet Formation ◽  
Liquid Droplets ◽  
Proof Of Concept ◽  
Aggregate Formation ◽  
Fused In Sarcoma ◽  
Dynamics Simulations

AbstractLiquid droplets of aggregation-prone proteins, which become hydrogels or form amyloid fibrils, are a potential target for drug discovery. In this study, we proposed an experiment-guided protocol for characterizing the design grammar of peptides that can regulate droplet formation and aggregation. The protocol essentially involves investigation of 19 amino acid additives and polymerization of the identified amino acids. As a proof of concept, we applied this protocol to fused in sarcoma (FUS). First, we evaluated 19 amino acid additives for an FUS solution and identified Arg and Tyr as suppressors of droplet formation. Molecular dynamics simulations suggested that the Arg additive interacts with specific residues of FUS, thereby inhibiting the cation–π and electrostatic interactions between the FUS molecules. Second, we observed that Arg polymers promote FUS droplet formation, unlike Arg monomers, by bridging the FUS molecules. Third, we found that the Arg additive suppressed solid aggregate formation of FUS, while Arg polymer enhanced it. Finally, we observed that amyloid-forming peptides induced the conversion of FUS droplets to solid aggregates of FUS. The developed protocol could be used for the primary design of peptides controlling liquid droplets and aggregates of proteins.

scholarly journals Molecular Dynamics Study of Ion Transport in Polymer Electrolytes of All-Solid-State Li-Ion Batteries

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1012
Author(s):  
Takuya Mabuchi ◽  
Koki Nakajima ◽  
Takashi Tokumasu
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Ion Transport ◽  
Polyethylene Oxide ◽  
Polymer Electrolytes ◽  
Li Ion Batteries ◽  
Transport Mechanisms ◽  
Li Ion ◽  
Dynamics Simulations ◽  
The Relationship

Atomistic analysis of the ion transport in polymer electrolytes for all-solid-state Li-ion batteries was performed using molecular dynamics simulations to investigate the relationship between Li-ion transport and polymer morphology. Polyethylene oxide (PEO) and poly(diethylene oxide-alt-oxymethylene), P(2EO-MO), were used as the electrolyte materials, and the effects of salt concentrations and polymer types on the ion transport properties were explored. The size and number of LiTFSI clusters were found to increase with increasing salt concentrations, leading to a decrease in ion diffusivity at high salt concentrations. The Li-ion transport mechanisms were further analyzed by calculating the inter/intra-hopping rate and distance at various ion concentrations in PEO and P(2EO-MO) polymers. While the balance between the rate and distance of inter-hopping was comparable for both PEO and P(2EO-MO), the intra-hopping rate and distance were found to be higher in PEO than in P(2EO-MO), leading to a higher diffusivity in PEO. The results of this study provide insights into the correlation between the nanoscopic structures of ion solvation and the dynamics of Li-ion transport in polymer electrolytes.

The Adsorption Characteristics and Mechanism of Pb(II) onto Corn Straw Biochar

2021 ◽  
Vol 15 (3) ◽  
pp. 287-295
Author(s):  
Liucheng Wang ◽  
Huanhuan Zhao ◽  
Xianglin Song ◽  
Yake Li ◽  
Dong Li
Keyword(s):  
Molecular Layer ◽  
Corn Straw ◽  
Adsorption Characteristics ◽  
Layer Adsorption ◽  
Adsorption Data ◽  
Renewable Material ◽  
Increasing Temperature ◽  
And Diffusion ◽  
Positive Effect ◽  
Single Molecular Layer

Heavy metal pollution has adversely affected the ecological environment. As an eco-friendly and renewable material, biochar has a positive effect on environmental restoration. For study the feasibility of removing lead using corn straw biochar, the adsorption characteristics and mechanism were studied. This work prepared corn straw biochar at 300 °C, and its surface properties were characterized. The adsorption kinetics, isotherm, thermodynamics were determined. The result indicated the mechanism belonged ion exchange and complexation, and the experiment were controlled by comprehensive process, which included reaction rate and diffusion. The Langmuir model had better fitting results for the adsorption data, which indicated that adsorption was chemical adsorption and single molecular layer adsorption, and the maximum adsorption amount of corn straw biochar at 25 °C, 35 °C and 45 °C were 81.63 mg/g, 83.89 mg/g and 89.21 mg/g respectively. The thermodynamic analysis showed that increasing temperature was helpful to adsorption, and the adsorption was spontaneous. The results can be used for comprehensive utilization of straw and treatment of lead pollution.

scholarly journals Solidification and superlubricity with molecular alkane films

2019 ◽  
Vol 116 (51) ◽  
pp. 25418-25423 ◽  
Author(s):  
Alexander M. Smith ◽  
James E. Hallett ◽  
Susan Perkin
Keyword(s):  
Solid Phase ◽  
Molecular Layer ◽  
Friction Coefficients ◽  
Model Studies ◽  
Surface Alignment ◽  
Hydrocarbon Films ◽  
Nanoscale Films ◽  
Alkane Films ◽  
And Control ◽  
Single Molecular Layer

Hydrocarbon films confined between smooth mica surfaces have long provided an experimental playground for model studies of structure and dynamics of confined liquids. However, fundamental questions regarding the phase behavior and shear properties in this simple system remain unsolved. With ultrasensitive resolution in film thickness and shear stress, and control over the crystallographic alignment of the confining surfaces, we here investigate the shear forces transmitted across nanoscale films of dodecane down to a single molecular layer. We resolve the conditions under which liquid–solid phase transitions occur and explain friction coefficients spanning several orders of magnitude. We find that commensurate surface alignment and presence of water at the interfaces each lead to moderate or high friction, whereas friction coefficients down toμ≈0.001are observed for a single molecular layer of dodecane trapped between crystallographically misaligned dry surfaces. This ultralow friction is attributed to sliding at the incommensurate interface between one of the mica surfaces and the laterally ordered solid molecular film, reconciling previous interpretations.

scholarly journals Ionic transport in highly concentrated lithium bis(fluorosulfonyl)amide electrolytes with keto ester solvents: structural implications for ion hopping conduction in liquid electrolytes

2019 ◽  
Vol 21 (9) ◽  
pp. 5097-5105 ◽  
Author(s):  
Shinji Kondou ◽  
Morgan L. Thomas ◽  
Toshihiko Mandai ◽  
Kazuhide Ueno ◽  
Kaoru Dokko ◽  
...  
Keyword(s):  
Ion Transport ◽  
Ion Pairs ◽  
Ionic Transport ◽  
Hopping Conduction ◽  
Keto Ester ◽  
Liquid Electrolytes ◽  
Li Ion

The hopping/exchange-dominated Li ion transport is attributed to liquid electrolytes with solvent-bridged, chain-like Li ion coordination and aggregated ion pairs.

Powder x-ray diffraction of turbostratically stacked layer systems

1996 ◽  
Vol 11 (7) ◽  
pp. 1733-1738 ◽  
Author(s):  
D. Yang ◽  
R. F. Frindt
Keyword(s):  
Special Form ◽  
Molecular Layer ◽  
X Ray Diffraction ◽  
Layer System ◽  
X Ray ◽  
Debye Formula ◽  
Diffraction Patterns ◽  
Single Molecular Layer ◽  
Deposition Conditions

A special form of the Debye formula for calculating the powder x-ray diffraction of a turbostratically stacked layer system is derived, and calculated diffraction patterns for turbostratically stacked graphite and MoS2 layers are presented. Single-molecular-layer MoS2, prepared by exfoliation of lithium-intercalated MoS2 in water or alcohols, has been deposited on various supports, and x-ray diffraction patterns show that the restacking of the MoS2 layers can be perfectly turbostratic. The restacked MoS2 may or may not have water or organic bilayers between them, depending on the deposition conditions.

The remarkable activity and stability of a dye-sensitized single molecular layer MoS2ensemble for photocatalytic hydrogen production

2015 ◽  
Vol 51 (70) ◽  
pp. 13496-13499 ◽  
Author(s):  
Tiantian Jia ◽  
Molly M. J. Li ◽  
Lin Ye ◽  
Sam Wiseman ◽  
Guoliang Liu ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Binding Affinity ◽  
Molecular Layer ◽  
Single Layer ◽  
Eosin Y ◽  
Photocatalytic Hydrogen Production ◽  
Dye Sensitized ◽  
Strong Binding ◽  
Single Molecular Layer ◽  
Dye Molecule

Single layer MoS2synthesized by exfoliation with Li is demonstrated to take up the dye molecule, Eosin Y, with strong binding affinityviasulfur vacancies.

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