Distinguishing nanobubbles from nanodroplets with AFM: the influence of vertical and lateral imaging forces

TL;DR

This paper demonstrates how atomic force microscopy (AFM) can differentiate nanobubbles from nanodroplets by analyzing their mechanical responses under different imaging forces, aiding in accurate identification.

Contribution

It introduces a method to distinguish nanobubbles from nanodroplets using AFM by examining their responses to vertical and lateral forces, addressing a key experimental challenge.

Findings

Nanobubbles and nanodroplets show distinct mechanical responses under AFM.

Vertical and lateral forces can be used to reliably identify nanobubbles.

The method helps prevent contamination and misidentification in experiments.

Abstract

The widespread application of surface-attached nanobubbles and nanodroplets in biomedical engineering and nanotechnology is limited by numerous experimental challenges, in particular, the possibility of contamination in nucleation experiments. These challenges are complicated by recent reports that it can be difficult to distinguish between nanoscale drops and bubbles. Here we identify clear differences in the mechanical responses of nanobubbles and nanodroplets under various modes of AFM imaging which subject the objects to predominantly vertical or lateral forces. This allows to distinguish between nanodroplets, nanobubbles, and oil covered nanobubbles in water.