Mechanistic Insights into Yielding and Fracture of Polymer Nanoparticles under Compression via All-Atom Molecular Dynamics Simulations for Applications in Anisotropic Conductive Adhesives

Polymer nanoparticles (PNPs) have gathered attention owing to their diverse applications; however, the mechanisms governing their mechanical properties and fracture behaviors remain unclear. All-atom molecular dynamics simulations were used to investigate the compressive fracture mechanisms of the PNPs. Poly(methyl methacrylate) and poly(methyl acrylate) nanoparticles were analyzed by focusing on their region-specific structural and mechanical responses. By defining the true stress based on the contact area between the nanoparticle and compression plate, we discovered that PNPs exhibit yielding behavior under compression. Region-specific analysis revealed a structural transition from the core to the middle region and a less dense surface region, causing inhomogeneous mechanical properties. These findings provide key insights into the structure–property relationships of glassy PNPs and establish a foundation for the design of materials of anisotropic conductive adhesives with tailored mechanical properties.