Interpreting the signal from a localized fluorescence sensor: a study by angle-resolved XPS and dynamic SIMS

Area of Science:

• Materials Science
• Surface Chemistry
• Polymer Science

Background:

• Understanding resin-silane interactions is crucial for advanced composite materials.
• Previous studies used fluorescent probes to track resin penetration and cure.
• Further investigation is needed for detailed analysis of hardener-silane layer interactions.

Purpose of the Study:

• To investigate the penetration and concentration profile of a diamine curing agent within a glycidoxysilane-modified glass substrate.
• To analyze the structural reorganization of the silane layer upon hardener exposure.
• To determine the anisotropy of the diamine/glycidoxysilane coating.

Main Methods:

• Angle-resolved X-ray photoelectron spectroscopy (XPS) for surface elemental composition and chemical states.
• Dynamic secondary ion mass spectroscopy (DSIMS) for depth profiling and concentration analysis.
• Analysis of silane layers exposed solely to the diamine hardener.

Main Results:

• DSIMS confirmed hardener presence throughout the silane layer via a strong CN- signal.
• XPS indicated an amine concentration gradient, decreasing with depth within the top 10 nm.
• XPS data suggested molecular anisotropy in the coating, evidenced by angle-dependent C1s peak analysis.

Conclusions:

• Diamine hardener penetrates the glycidoxysilane layer, leading to a concentration gradient.
• The silane layer exhibits structural reorganization and molecular anisotropy upon hardener interaction.
• These findings provide detailed insights into the interfacial chemistry relevant to composite material performance.