Mechanochemical Activation of a Metal–Organic Framework Embedded within a Thermoplastic Polyurethane Matrix: Probing Fluorogenic Stress‐Sensing

• DOI: 10.1002/macp.202300297
• Publication Date: 2023-09-25T14:29:06Z
• Authors: Kshitij Sanjay Sh...; Philipp Michael; Wolfgang H. Binder
• Keywords: Thermoplastic polyurethane

Abstract Here, a mechanochemically triggered Cu(I) bis( N ‐heterocyclic carbene [NHC))‐based metal–organic framwork (MOF) embedded into thermoplastic polyurethane (TPU)‐matrix is reported. The induced fluorogenic copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reveals the stressed parts within PU via simple optical detection. As determined oscillating tensile rheology on dumbbell‐shaped samples of TPU, MOF, containing 4.66% copper, catalyzes CuAAC between nonfluorescent precursor dyes, 8‐azidonaphthalen‐2‐ol, and 3‐hydroxyphenylacetylene. After mechanical activation MOF situated inside fluorescent 8‐(4‐(3‐hydroxyphenyl)‐1,2,3‐triazol‐1‐yl)naphthalen‐2‐ol dye formed. Monitoring formation TPU fluorescence spectrometry at λ ex = 458 nm shows an increase intensity up to 60–70%. It demonstrated that subjected higher stress, displays than surrounding other areas, thus effectively functioning as three‐in‐one stress‐sensor system.