Ion transport across solid-state ion channels perturbed by directed strain.

Area of Science:

• Computational materials science
• Physical chemistry
• Nanotechnology

Background:

• Understanding ion transport through nanopores is crucial for biological and artificial systems.
• Graphene and Molybdenum disulfide (MoS2) are promising 2D materials for nanopore fabrication.
• Anisotropic properties in materials can lead to novel functionalities.

Purpose of the Study:

• To investigate the directional dependence of aqueous ion flow across non-axisymmetric nanopores in graphene and MoS2 under tensile strain.
• To elucidate the relationship between pore geometry, local electrostatics, and ion permeability anisotropy.
• To explore the potential for developing functional nanopores based on anisotropic ion transport.

Main Methods:

• Quantum-chemical calculations were employed to model atomic interactions and electronic properties.
• Molecular dynamics simulations were used to simulate aqueous ion flow across nanopores.
• Uniaxial tensile strains were applied in various directions to study their effect on pore properties.

Main Results:

• Aqueous ion permeability across graphene and MoS2 nanopores exhibited significant directional dependence (anisotropy) under strain.
• The observed anisotropy was attributed to strain-induced perturbations in local electrostatics, influenced by pore edge geometry and composition.
• The degree of anisotropy varied with the direction of applied strain.

Conclusions:

• Non-axisymmetric nanopores in 2D materials display tunable anisotropic ion transport properties.
• This anisotropic behavior provides a pathway to understand the structure-function relationships in ion channels.
• The findings facilitate the design of sub-nanoscale pores with tailored functionalities for applications in sensing and separation.