What is it about?
Self-assembled monolayers (SAMs) are one of those systems that never stop surprising us with their structural sophistication. They have been known and studied for nearly 80 years, yet much about them is still unknown. Understanding these systems is challenging, and so is the task of creating accurate computer models that can capture their structure and properties under different conditions. The molecules position themselves with precise alignment over the atoms of the surface, forming regular patterns whose orientations depend on factors such as temperature and chain length. In our work, we tackled the challenge of building a nanoscale, atom-by-atom computer model of SAMs on gold surfaces. We focused on alkanethiols—the simplest and most studied class of SAM-forming molecules, made up of a long carbon-hydrogen chain ending in a sulphur atom that bonds to gold. Our modelling method can produce accurate parameters for any classic force field and can be applied to any ligand-surface combination.
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Why is it important?
Interest in SAMs is growing fast because they play a role in many emerging technologies—from sensors that detect tiny amounts of chemicals, to flexible electronics that can be built into wearable devices or foldable screens, protective surface coatings, medical implants, and new ways of building materials at the nanoscale. Our interest in SAMs on gold came from a bigger goal: simulating a new nanofabrication method called photoassisted chemical vapour deposition (PACVD), which deposits metals on surfaces at near room temperature using light instead of heat. This is an energy-efficient approach ideal for delicate materials like organic thin films used in solar cells. However, optimizing these technologies requires a detailed understanding of how SAMs work on the molecular level, and computational models are essential aids in this endeavour.
Perspectives
There is still plenty to learn about SAMs, from how chain length and mixed compositions affect their structure to how they can be tailored for biocompatible platforms, electronics, and sensing. Even the classic alkanethiol-on-gold system keeps delivering surprises. We hope our modelling framework will give researchers a powerful new way to explore these systems in silico and uncover the design rules that will drive the next generation of SAM-based technologies.
Cauê Souza
University of Kent
Read the Original
This page is a summary of: A refined atomistic model of functionalized self-assembled monolayers on gold: Assessment of force field parameters, The Journal of Chemical Physics, September 2025, American Institute of Physics,
DOI: 10.1063/5.0274290.
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