Angioletti-Uberti, S.; Lu, Y.; Ballauff, M.; Dzubiella, J.: Theory of Solvation-Controlled Reactions in Stimuli-Responsive Nanoreactors. The Journal of Physical Chemistry C 119 (2015), p. 15723-15730
Open Accesn Version

Metallic nanoparticles embedded in stimuli-responsive polymers can be regarded as nanoreactors because their catalytic activity can be changed within wide limits: the physicochemical properties of the polymer network can be tuned and switched by external parameters, for example, temperature or pH, and thus allow a selective control of reactant mobility and concentration close to the reaction site. Combining Debye’s model of diffusion through an energy landscape and a two-state model for the polymer, here we develop an analytical expression for the observed reaction rate constant, kobs. Our formula shows an exponential dependence of this rate on the solvation free-enthalpy change ΔG̅sol, a quantity that describes the partitioning of the reactant in the network versus bulk. Thus, changes in ΔG̅sol, and not in the diffusion coefficient, will be the decisive factor affecting the reaction rate in most cases. A comparison with recent experimental data on switchable, thermosensitive nanoreactors demonstrates the general validity of the concept.