Phase stability of colloidal spheres mixed with supramolecular rod‐like polymers

Mixtures of colloids and supramolecular polymers exhibit stimuli‐responsive phase behavior. In previous work (Peters and Tuinier, Physica A 510, 233 [2018]) the polymers were treated as fully flexible chains, while in experimental systems supramolecular polymers may have a certain degree of stiffness. Here we predict that for stiff rod‐like supramolecular polymers phase separation can occur at much lower polymer concentrations than for flexible supramolecular polymers. Additionally, it is demonstrated that colloid–polymer interactions can significantly influence the equilibrium polymer size distribution, however this does not strongly affect the phase behavior of the mixture. At the low polymer concentrations at which the system already gets unstable, the effect of excluded volume interactions between polymers chains themselves is small. Finally, for an experimental system it is predicted that a variety of re‐entrant phase transitions may be observed within a realistic temperature range as illustrated by a specific example. This theoretical study shows that supramolecular polymers, especially rod‐like ones mixed with nonadsorbing colloidal spheres, appear to be excellent candidates for enabling responsive phase transition materials. Multiple thermoresponsive changes in the phase state are predicted to occur in realistic temperature windows.