Mechanochemical Transduction of Externally Applied Forces to Mechanophores

We present a theoretical study on the role played by aliphatic polymer chains in the transduction of external forces to mechanophores being at the heart of force spectroscopy and sonication experiments. Upon introducing a rigorous approach rooted in catastrophe theory, we demonstrate that the rupture force of a cis 1,2-disubstituted benzocyclobutene features a remarkable dependence, including odd-even effects, on the length of attached polymer chains. This unexpected finding is furthermore rationalized by establishing a correlation between the rupture force and local distortions of the mechanophore at its junctions with the transducing chains. The force-transformed Hessians unveil a surprising force-dependence of harmonic force constants associated with relevant structural parameters of these chains. Not only do our findings highlight the necessity of taking into account the polymer chains explicitly when thinking about mechanochemical manipulation, but they also announce the possibility of tuning the properties of mechanoresponsive polymers by tailoring the force-transducing chain molecules.