Hydrocarbon Contamination in Angstrom-scale Channels

TL;DR

This paper investigates hydrocarbon contamination in angstrom-scale nanochannels, revealing how size-dependent clogging occurs, and demonstrates the channels' stability and self-cleansing ability over long periods, which is crucial for nanofluidic applications.

Contribution

It provides a systematic study of hydrocarbon adsorption effects in angstrom-scale channels, introducing a method to assess cleanliness and demonstrating long-term stability and self-cleansing properties.

Findings

Clogging depends on channel and hydrocarbon size difference.

Sub-2 nm channels show dynamic clogging and revival behavior.

Channels remain stable and self-cleaning over three years.

Abstract

Nonspecific molecular adsorption like airborne contamination occurs on most surfaces including those of 2D materials and alters their properties. While the surface contamination is studied using a plethora of techniques, the effect of contamination on a confined system such as nanochannels, nanopores leading to their clogging is still lacking. We report a systematic investigation of hydrocarbon adsorption in the angstrom slit channels of varied heights. Hexane is chosen to mimic the hydrocarbon contamination and the clogging of the angstrom-channels is evaluated via a Helium gas flow measurement. The level of the hexane adsorption, in other words, the degree of clogging depends on the size difference between the channels and hexane. A dynamic transition of the clogging and revival process is shown in sub-2 nm thin channels. Long-term storage and stability of our angstrom-channels is demonstrated here up to three years, alleviating the contamination and unclogging the channels using thermal treatment. This study highlights the importance of the nanochannels stability and demonstrates self-cleansing nature of sub-2 nm thin channels enabling a robust platform for molecular transport and separation studies. We provide a method to assess the cleanliness of the nanoporous membranes, which is vital for the practical applications of nanofluidics in various fields such as molecular sensing, separation and power generation.