Molecular transport in nanopores with fluctuations, deformation, and potential leakage

Noh, Yechan

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https://hdl.handle.net/2142/121405 Copy

Description

Title

Molecular transport in nanopores with fluctuations, deformation, and potential leakage

Author(s)

Noh, Yechan

Issue Date

2023-07-07

Director of Research (if dissertation) or Advisor (if thesis)

Aluru, Narayana R

Doctoral Committee Chair(s)

• Aluru, Narayana R
• van der Zande, Arend

Committee Member(s)

• Saif, Taher A
• Zhang, Yingjie

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Water transport, two dimensional membranes, nanopore, ion transport, surface charge density, water desalination, and nanofluidics.

Abstract

Nanofluidics is a rapidly growing field centered on the transport phenomena of fluids and ions in nanopores and membranes. In this thesis, we examine the impact of vibrational coupling between nanopores/membranes and fluids/ions on various transport properties through molecular dynamics simulations. Specifically, we investigate water desalination in fluctuating 2D porous membranes; the influence of interfacial vibrational coupling on surface wettability and wall-fluid friction; the activation of atomic transport via vibrational coupling; ion transport in 2D flexible nanoporous membranes; ion transport in electrically imperfect nanopores; and the scaling behavior of ion conductance in fluctuating 2D membranes. We investigate the impact of vibrational coupling between fluids and nanopores on transport phenomena. Our results show that vibrational coupling plays a crucial role in molecular transport phenomena. We demonstrate that the microscopic vibrations of nanopores/membranes can significantly affect transport properties, such as water permeation rate, surface wettability, wall-fluid friction, and ion transport. Furthermore, we show that atomic transport can be activated due to the enhanced force fluctuations caused by vibrational coupling. These findings have important implications for designing efficient and effective nanofluidic devices and membranes for various applications, including water desalination, ion separation, and molecular sensing. We study the scaling relation between ion conduction and ion concentration in nanopores. Our results reveal that the leakage of pore potential in thin nanopores can significantly affect ion transport. We find that the electric potential leaks out of the pore when the thickness of the pore is thin, and the degree of leakage determines the power law exponent between conductance and concentration. Moreover, we demonstrate that fluctuations in 2D porous membranes can alter the power-law exponent of ion conductance. These findings provide a fundamental understanding of microscopic ion transport and have important implications for estimating electrical properties of nanopores and manipulating ion current by deforming membranes. Overall, this thesis provides fundamental insights into molecular transport phenomena and highlights the importance of considering vibrational coupling effects in the design and optimization of nanofluidic devices and membranes. The significance of our research lies in offering valuable guidance for the development of improved nanofluidic devices and membranes for various applications, thus making a substantial impact on the nanofluidics community.

Graduation Semester

2023-08

Type of Resource

Thesis

Copyright and License Information

© 2023 Yechan Noh

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