Hierarchical Mechanisms of Lateral Interactions in High-Performance Fibers

Area of Science:

• Materials Science
• Polymer Science
• Mechanical Engineering

Background:

• Advanced polymer fibers possess hierarchical structures influencing mechanical properties.
• Previous research focused on nanoscale or global fracture, neglecting intermediate-scale interfacial interactions.

Purpose of the Study:

• To investigate interfacial interactions at the intermediate length scale (hundreds of nanometers) in advanced polymer fibers.
• To elucidate the role of these interactions in fiber tensile fracture and overall mechanical performance.

Main Methods:

• Developed a focused ion beam (FIB) sample preparation protocol.
• Utilized nanoindentation to probe interfaces in poly(p-phenylene terephthalamide) and ultrahigh molecular weight polyethylene fibers.

Main Results:

• Quantified higher interfacial separation energy in rigid-rod fibers, correlating with reduced fibrillation.
• Observed power law scaling and self-similar energy absorption mechanisms in flexible chain fibers.
• Identified distinct energy absorption mechanisms at the intermediate scale.

Conclusions:

• The intermediate length scale is crucial for understanding polymer fiber failure mechanisms.
• Hierarchical interfacial interactions significantly impact mechanical performance.
• Findings will guide the design of novel high-performance polymer fibers.