Self‐Immolative Gels: Programmable Degradation Using Self‐Immolative Linkers and Polymers

Gels have diverse structures and properties, making them of interest for a broad range of applications from pollution control to regenerative medicine. The controlled and stimulus-triggered breakdown or property modulation of gels can lead to specific functions, such as sensing or drug release. Self-immolative linkers (SILs) and self-immolative polymers (SIPs) benefit from reaction cascades that allow a single stimulus-mediated bond cleavage event to be translated across multiple bonds or even along an entire polymer chain. In this Concept article, we begin by introducing the chemistry fundamentals behind SILs and SIPs. Then, the incorporation of SILs into gel systems through cargo modification and their use in cross-linkers is presented. We then discuss SIP organogels and how SIP systems have been imparted with the hydrophilic components needed to achieve hydrogels. A focus is given to the chemistry involved, and how this chemistry can be harnessed for potential applications. Finally, we present a summary and outlook for the field, examining the current status, and directions for future work.