Building From the Ground Up: A Procedural Guide to Locally Controlling Bond Exchange Kinetics in Dynamic Thiol‐Thioester Networks

Covalent adaptable networks (CANs) are a new class of polymers possessing the structural robustness of classical thermosets and stimuli‐dependent malleability of thermoplastics, imparting them with repairability, reprocessability, and recyclability potential. These CANs can even be tailored to have spatially controllable properties and enhanced functionality; however, the introduction of additional reactive moieties leads to inadvertent side reactions and deterioration of the desired performance. Herein, we present a comprehensive approach to the optimization of locally controllable CANs, relying on base catalyzed thiol‐thioester exchange reactions. The network is formed by visible light (405/450 nm) induced radical thiol‐ene polymerization, whilst local deactivation of the dynamic exchange reaction is achieved by neutralizing the basic catalyst with a photoacid generated upon UV‐light (365 nm) exposure. The intricate interactions between the resin components were studied, and the factors affecting the network performance were investigated to provide a detailed account of the development process, from the rational selection of initial components to the systematic optimization of a locally controlled, photoswitchable CAN. Finally, its on‐demand tunability is demonstrated by surface‐ and bulk shape reconfiguration through heat‐assisted processes.