UC San Diego

Polymers are an important class of materials with a broad spectrum of mechanical properties that warrant their utility in various applications. Modern polymer characterization techniques have been valuable in providing multiscale insight into the structure and properties, including molecular structure and morphology, and thermal and mechanical properties, respectively. However, these techniques have been performed postmortem or have limitations that are unsuitable for in-situ characterization. The latter hinders the complete understanding of dynamic mechanical responses in polymers and the corresponding fundamental molecular mechanisms. Therefore, this research aims to develop a novel experimental solid mechanics setup capable of loading elastomeric polymers at various strain rates while concurrently interrogating the sample with a bulk spectroscopic technique using terahertz waves. The resulting time and frequency domains data and the supporting micrographs, computational and analytical solutions, digital image correlation, and light-matter interaction analyses substantiate the validity of utilizing terahertz-based spectroscopy to capture the underlying molecular mechanisms of mechanically loaded polymers. Furthermore, the fundamental insight gained through the in-situ spatiotemporal characterization of dynamically loaded polymers will accelerate the development of shock-tolerant and impact-resistant materials.