Interfacial Binding Energy between Calcium-Silicate-Hydrates and Epoxy Resin: A Molecular Dynamics Study

Area of Science:

• Materials Science
• Chemical Engineering
• Civil Engineering

Background:

• Self-healing materials utilize microcapsules with epoxy curing agents to repair damage.
• The effectiveness of these materials hinges on the epoxy curing agent's interaction with the cement matrix.
• Understanding this interface is crucial for optimizing self-healing capabilities.

Purpose of the Study:

• To investigate the interfacial binding energy between epoxy curing agents and cement using molecular dynamics simulation.
• To analyze the influence of molecular structure, including chain length and direction, on binding energy.
• To identify optimal components for enhanced binding in microcapsule-based self-healing systems.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model interactions at the molecular level.
• Seven distinct molecular models were constructed, varying epoxy, curing agents, and dilutants.
• Key parameters investigated included chain length, curing agent type, and epoxy resin chain orientation.

Main Results:

• Increasing chain length had a minimal effect on interfacial binding energy.
• The choice of curing agent and the direction of the epoxy resin chains significantly influenced binding energy.
• Tetrethylenepentamine demonstrated the highest interfacial binding energy, increasing it by 31.03 kcal/mol.

Conclusions:

• The curing agent is a critical factor in determining the binding ability of microcapsules within cement matrices.
• Tetrethylenepentamine shows superior binding potential for microcapsule-based self-healing concrete.
• This research provides fundamental molecular-level insights into interface behavior for advanced material design.