Mechanochromic polymer composites have many applications as force sensors due to their ability to indicate mechanical forces as a change in their optical properties. Recent studies have revealed the unique mechanically-sensitive optical properties of gold nanoparticles (AuNPs), yet their behaviors in polymer materials have not yet been investigated. In this study, different concentrations of epoxy-AuNPs composites with various sized particles were synthesized and characterized. Here, we established a method for synthesizing epoxy-AuNPs composites by stabilizing particles with a ligand capable of crosslinking with the polymer matrix. Citrate-capped AuNPs were first ligand exchanged with amine-polyethylene glycol (PEG)-thiol and incorporated into the epoxy resin, bisphenol A diglycidyl ether (DGEBA). The epoxy composites with amine-PEG-thiol-stabilized AuNPs produced uniform absorbance unaltered by polymerization, suggesting good dispersion and stability of the particles in the epoxy polymer. The crosslinking was also characterized by Raman spectroscopy and <sup>1</sup>H NMR. We further confirmed that the addition of NPs in the epoxy resin does not affect the degree of curing, mechanical or thermal properties of the epoxy. These nanocomposites will be further investigated to analyze the change in optical properties while applying tensile and compressive forces.

Applying gold nanoparticles as force sensors in epoxy polymers: Synthesis and characterizations of epoxy nanocomposites

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.