Detectable Catechol-Containing Adhesives with High Performance Efficiently Prepared by ROMP and Complexation

Although numerous catechol-containing adhesives have been reported, they generally suffer from the absence of real-time detection functionality, which limits their applications in intelligent manufacturing. Herein, we present a simulation-guided strategy via ring-opening metathesis polymerization (ROMP) and metal-ligand coordination to construct strong, electrically detectable catechol-containing adhesives. Initially, the homopolymer poly(3-(3,4-dihydroxy-phenyl)–2-[2-(3,5-dioxo-4-aza-tricyclo dec-8-en-4-yl)-ethoxycarbonylamino]-propionic acid methyl ester) (PDOPA200) exhibited a limited bonding strength of only 0.67 ± 0.02 MPa. To overcome this, molecular dynamics (MD) simulations were employed to investigate the influence of copolymers’ composition and structure on the bonding performance. The reactivity ratios of comonomers were determined to be 0.50 and 1.29, respectively, which suggests the formation of a gradient architecture during one-pot copolymerization. Both simulations and experiments confirmed that, compared to sequentially added block copolymers, the gradient copolymer with 40 mol % poly 4-(2-hydroxy-1-hydroxymethyl-1-methyl-ethyl)–4-aza-tricycl dec-8-ene-3,5-dione (P2OH) and a degree of polymerization of 200 achieved the highest bonding strength of 4.1 ± 0.08 MPa, which was further enhanced to 7.5 ± 0.06 MPa after complexation with Fe3+. Moreover, the obtained catechol–Fe3+ complex adhesives possess excellent solvent (acetonitrile, hexane, ethanol, acid solution, water, and artificial seawater) resistance and wide applications, especially in real-time crack/failure detection of the adhesive. The obtained catechol-containing adhesives can expand the variety of detectable adhesives and have great application prospects in intelligent manufacturing.