An In-Depth Investigation of the Effect of Curing Temperature on Spiropyran Mechanophore Activation in Bulk PDMS under Dynamic Loading
Abstract
Embedded in the silicone elastomer polydimethylsiloxane (PDMS), the spiropyran mechanophore mechanochemically changes color under applied load, linking molecular-level behavior to macro-scale loading. As the spiropyran is covalently linked to the PDMS polymer chain, the mechanical properties of the silicone elastomer substrate play a large role in the materials behavior and timing of mechanochromism. Here, the influence of the PDMS curing temperature on material behavior and mechanochromic response of the embedded spiropyran is studied under uniaxial dynamic compression at rates of 1000 s-1. Higher curing temperatures are shown to produce stiffer material, which requires increased stress to initiate color change. However, a consistent onset strain of approximately 90 percent is needed, regardless of stress. These results suggest activation is strain controlled, and that increasing cross-linking density, coupled with the corresponding reduction in stretchability, increases the force required to reach a consistent activation strain.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2021
- Accession Number
- AD1149344
Entities
People
- James Berry
- Logan Shannahan
- Müge Fermen-coker
- Stephen L Craig
Organizations
- United States Army Research Laboratory