Interlocking mechanism between molecular gears attached to surfaces

TL;DR

This paper investigates the mechanisms of molecular gears on surfaces using ab initio calculations, revealing how they transmit rotational motion and differ from macroscopic gears, with implications for designing molecular machines.

Contribution

It provides detailed insights into the intermolecular interactions and motion transmission in molecular gears, a fundamental component for future nanoscale machinery, using computational modeling.

Findings

Transmission of slow rotational motion between gears elucidated

Flexibility and slipping behaviors of molecular gears characterized

Theoretical concepts suggest potential for designing larger molecular machines

Abstract

While molecular machines play an increasingly significant role in nanoscience research and applications, there remains a shortage of investigations and understanding of the molecular gear (cogwheel), which is an indispensable and fundamental component to drive a larger correlated molecular machine system. Employing ab initio calculations, we investigate model systems consisting of molecules adsorbed on metal or graphene surfaces, ranging from very simple triple-arm gears such as PF3 and NH3 to larger multi-arm gears based on carbon rings. We explore in detail the transmission of slow rotational motion from one gear to the next by these relatively simple molecules, so as to isolate and reveal the mechanisms of the relevant intermolecular interactions. Several characteristics of molecular gears are discussed, in particular the flexibility of the arms and the slipping and skipping between interlocking arms of adjacent gears, which differ from familiar macroscopic rigid gears. The underlying theoretical concepts suggest strongly that other analogous structures may also exhibit similar behavior which may inspire future exploration in designing large correlated molecular machines.