(a) Structures of the thiol, thioester containing alkene, and photoinitiator used to synthesize adhesive films as well as the nucleophilic thiol-thioester exchange catalyst. All samples contain 1 equiv of PETMP, 1 equiv of TE-diene, 1 wt % I819 relative to the monomers, and various mol % DABCO relative to TE-diene. (b) General scheme of thiol-thioester exchange. (c) Stress relaxation curves for thiol–ene adhesives with various mol % DABCO as the nucleophilic catalyst at an applied strain of 5%.