Visualizing Shockwave Interactions and Sub-Catastrophic Damage in Materials via Mechanophores

Published

October 7, 2024

Author(s)

Polette Centellas, Kyle Mehringer, Andrew Bowman, Katherine Evans, Parth Vagholkar, Travis Thornell, Liping Huang, Sarah Morgan, Christopher Soles, Yoan Simon, Edwin Chan

Abstract

Understanding the physical and chemical response of materials to impulsive deformation is crucial for applications ranging from soft robotic locomotion to space exploration to seismology. However, investigating material properties at extreme strain rates remains challenging due to temporal and spatial resolution limitations. Combining high-strain-rate testing with mechanochemistry uniquely encodes the molecular-level deformation within the material itself, thus enabling the direct quantification of the material response. Here, we demonstrate a mechanophore-functionalized block copolymer that self-reports unique energy dissipation mechanisms, such as bond rupture and acoustic wave dissipation, in response to high-strain-rate impacts. A microprojectile accelerated towards the polymer permanently deforms the material at a shallow depth. At intersonic velocities, the polymer reports significant subsurface energy absorption due to shockwave attenuation, a mechanism traditionally considered negligible compared to plasticity and not well explored in polymers. The acoustic wave velocity of the material is directly recovered from the mechanochemically-activated subsurface volume recorded in the material, which is validated by simulations, theory, and acoustic measurements. This integration of mechanochemistry with microballistic testing enables characterization of high-strain-rate mechanical properties and elucidates new insights applicable to nanomaterials, particle-reinforced composites, and biocompatible polymers.

Citation

Nature

Pub Type

Journals

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Keywords

polymer mechanochemistry, microballistic impact, block copolymer, mechanical properties

Citation

Centellas, P. , Mehringer, K. , Bowman, A. , Evans, K. , Vagholkar, P. , Thornell, T. , Huang, L. , Morgan, S. , Soles, C. , Simon, Y. and Chan, E. (2024), Visualizing Shockwave Interactions and Sub-Catastrophic Damage in Materials via Mechanophores, Nature, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=957459 (Accessed November 21, 2024)