Born-Haber cycle for monolayer self-assembly at the liquid-solid interface: assessing the enthalpic driving force

Area of Science:

• Physical Chemistry
• Surface Science
• Thermodynamics

Background:

• Monolayer self-assembly at liquid-solid interfaces involves solute molecules transitioning from a dissolved state to an adsorbed monolayer.
• Understanding the thermodynamic driving forces, particularly enthalpy and entropy changes, is crucial for controlling self-assembly processes.

Purpose of the Study:

• To present an adapted Born-Haber cycle for accurately determining enthalpy values in liquid-solid interface self-assembly.
• To provide a profound thermodynamic understanding of monolayer self-assembly processes.

Main Methods:

• Utilized an adapted Born-Haber cycle approach.
• Employed terephthalic acid as a model system for self-assembly studies.
• Assessed enthalpy differences using both experimental and theoretical methods for well-defined reference states.

Main Results:

• Successfully obtained precise enthalpy values for the self-assembly of interfacial monolayers.
• Demonstrated consistent assessment of enthalpy differences through independent experimental and theoretical calculations.
• Quantitatively compared enthalpy gain with entropy cost, highlighting contributions from solvation and dewetting.

Conclusions:

• The adapted Born-Haber cycle provides a reliable method for calculating self-assembly enthalpy at the liquid-solid interface.
• Solvation and dewetting effects significantly reduce the entropic cost, making monolayer self-assembly a thermodynamically favorable process.
• This thermodynamic understanding is key for designing and controlling self-assembled monolayers.