Expanding Gelation Conditions in Dynamically Crosslinked Networks

Polymer networks with dynamic physical crosslinks have generate widespread interest as tunable and responsive viscoelastic materials. A subclass of these materials containing multi-component, or complimentary, crosslinks, such as host-guest interactions and metal-coordination, are limited by their ability to percolate under stoichiometric imbalances of their crosslink components. Here we present a method to relax this stoichiometric requirement through the use of a third component, a dynamic, free competitor. This approach to expand the conditions that result in gelation is demonstrated experimentally with metal-coordinated hydrogels, and simulations are used to show the thermodynamic criteria that are necessary to expand the previously understood tight stoichiometric tolerance for gelation. This work can then be generally applied to advance engineering of the broadening class of polymer materials with dynamic crosslinks.