Mechanically Characterizing Polymeric Materials Using Buckling Mechanics and Mechanophores

In order for new materials to be implemented into industrial practice, rigorous characterization and performance assessment must be conducted. The ability to accurately characterize and assess these new materials is directly related to the delay between material development and implementation. Traditionally utilized characterization techniques may not be an appropriate method to characterize a material or materials system, thus warranting the development of new characterization and performance assessment techniques. For swift implementation of novel materials and materials systems, characterization and performance assessment methodologies must be developed simultaneously.

While many new materials characterization techniques have been developed over the past years, one area in need of further development is mechanical characterization techniques. For newly developed materials, understanding and accurately predicting the mechanical performance is essential for personnel safety and for preventing unexpected materials failure. The work presented here focuses on the development of mechanical characterization techniques employing two strategies: repurposing old tools and techniques to solve new problems and developing new tools and techniques to solve old problems.

By using the first strategy, classical buckling mechanics were deployed to create a robust elastic modulus characterization technique for brittle, glassy polymer films, and a technique developed to determine the “handle” or drape of textiles was repurposed to characterize the elastic modulus of temporary pavement marking tape to assess adhesion performance. Through the second strategy, newly developed molecules called Mechanophores (MP) that exhibit a color or fluorescence change upon the application of a mechanical stimulus are being considered for self-reporting damage sensing applications in polymeric material systems. The elicited fluorescent MP response increases with applied stress allowing for real time damage sensing that can prevent unexpected material failure. Here, a methodology is presented that calibrates the fluorescence MP response to applied stress. These strategies and methodologies can either be utilized or used as inspiration by other engineers for the development of material characterization methods for the rapid implementation of new materials into industrial practices.