The objective of the Sustainable Composites Project at NIST is to develop tools for measuring the fundamental structure-processing and structure -property relations associated with sustainable polymer composites. One area of study is mechanically activated leuco dyes (mechanophores), which have been recently proposed and are being tested as damage sensors in polymeric materials. The use of such dyes is particularly promising as a means to understand the polymer composite interphase, where load transfer between the matrix and the filler is difficult to measure directly. Here, we use a multi-faceted modeling approach to understand the activation of these dyes in at the interface of cross-linked epoxy-nanocellulose composites. Density functional theory (DFT) calculations are used to quantify the forces and the energetics involved in the mechanical activation of mechanophores. This information is then used to parameterize a bond-breaking potential to be used in molecular dynamics simulations of atomistic models of interphases in cross-linked epoxy based composites. This approach allows us to study the necessary conditions for the activation of the mechanophores at the matrix-filler interface.

Mechanophore activation at the crosslinked epoxy-nanocellulose interface: Insight from density functional theory and molecular dynamics simulations

253rd National Meeting (2017)

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