The impact of interfacial material properties on nanofluidic transport from weak to ultraconfinement

• Applicant: Dr. Hanne Antila
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 533645981

Within the last decade, a rapidly growing industry has formed around micro- and nanofluidics---the manipulation of solvent and solutes in channels ranging from a few nanometers to hundreds of micrometers. These techniques have a wide range of applications from energy harvesting to the analysis of biomolecules, where the small size of the devices provides number of advantages, such as low energy requirement, high resolution, massive parallelizability, and high speed of transport in the presence of slip. The further development of micro- and nanofluidic techniques requires a detailed understanding of the complex interplay of electrostatic and hydrodynamic interactions that governs the transport within the channels. This poses a great challenge, especially as the device size decreases: at the nanoscale, the finite size of the molecules and wall effects become significant, culminating in a rise of novel transport phenomena in devices with single-digit nanometer dimensions (ultraconfinement). Therein, understanding transport solely based on experimental information or continuum theories grows more complicated. The goal of this work is to harness the power of multi-scale molecular dynamics simulations to provide fundamental understanding on how interfacial effects affect transport in micro- and nanofluidic devices. Specifically, the effect of nanochannel dielectric properties will be investigated over a range of length scales. Simulations will elaborate how dielectrics can be coupled with other wall effects---structural surface charge and ion adsorption-desorption---to enable precise control over the movements of solvent and solutes, and how asymmetry in the wall properties can be used to further tailor the flow profile and enable new modes of transport. The systems studied will be chosen so that they are able both to provide information on the underlying, basic mechanisms governing transport over the length scales, and to demonstrate the role of surface properties in technological applications such as macromolecule separation.This project is timely as the increase in available computational capacity, and the recent development in simulation methods, finally enables simulations of nano- and microfluidics in experimentally relevant length- and time-scale, while fully taking account both the hydrodynamics and electrostatics of the system. Simultaneously, experimental advances have pushed nanofluidics into ultraconfinement region, where a wealth of new transport phenomena with technological potential but also significant knowledge gaps, exist.

• DFG Programme: Research Grants