Angstrofluidics: walking to the limit

TL;DR

This paper reviews recent advances in the fabrication, measurement, and understanding of angstrofluidic channels, emphasizing their potential for developing smart ionic devices and exploring ionic transport at the atomic scale.

Contribution

It categorizes fabrication methods for nano- and angstrofluidic channels based on dimensionality and compares ionic transport phenomena across different pore sizes.

Findings

Advances in atomically thin 2D materials enable Angstrom-scale fluidic channels.

Measurement techniques have evolved to characterize ionic transport at atomic scales.

Future opportunities include developing smart ionic devices with these channels.

Abstract

Angstrom-scale fluidic channels are ubiquitous in nature, and play an important role in regulating cellular traffic, signaling, and responding to stimuli. Synthetic channels are now a reality with the emergence of several cutting-edge bottom-up and top-down fabrication methods. In particular, the use of atomically thin two dimensional (2D) materials and nanotubes as components to build fluidic conduits has pushed the limits of fabrication to the Angstrom-scale. Here, we provide an overview of the recent developments in the fabrication methods for nano- and angstrofluidic channels while categorizing them on the basis of dimensionality (0D pores, 1D tubes, 2D slits), along with the latest advances in measurement techniques. We discuss the ionic transport governed by various stimuli in these channels and draw comparison of ionic mobility, streaming and osmotic power, with varying pore sizes across all the dimensionalities. Towards the end of the review, we highlight the unique future opportunities in the development of smart ionic devices.