A coumarin dimer probe of mechanochemical scission efficiency in the sonochemical activation of chain-centered mechanophore polymersElectronic supplementary information (ESI) available: Detailed experimental procedures, 1H NMR and 13C NMR spectra. See DOI: 10.1039/c5cc01836f

Here we present a coumarin dimer (CD) mechanophore that, when embedded near the mid-chain of poly(methyl acrylate) polymers, activates under pulsed ultrasound conditions to yield coumarin chain-end functional polymers. Quantitative photochemical scission of the CD polymers provides a reference against which the activation efficiency of chain-centered mechanophores in polymers synthesized by controlled/living radical polymerization (CRP) can be assessed. Activation efficiency is characterized with respect to the polymer molecular weight (MW), polydispersity index (PDI), and distribution of mechanophores along the backbone. A coumarin dimer mechanophore is used to probe the effect of polymer size and polydispersity on mechanochemical activation.