Photo-triggered Sustainable Adhesive Based on Itaconic Acid

Photoadhesives have been beneficial for a plethora of applications due to advantages in spatiotemporal control, flexible operating temperature, and in situ applicability. As a sustainable approach, bio-based precursors have been applied for the production of photoadhesives. However, the use of toxic chemicals and incorporation of petroleum-based chemicals in the synthesis process is inevitable. In this study, a photocurable itaconic acid-based polyester, poly­(1,3-propanediol-co-citrate-co-itaconate-co-1,12-dodecanedioate) (IAP), was developed from bio-based precursors through a facile, catalyst-free, and solvent-free polycondensation process without use of toxic chemicals. Ultraviolet (UV)-triggered photocross-linking in the presence of a photoinitiator was found to induce adhesion capability in IAP. With 30 min of UV exposure, IAP presented an adhesion strength of 1286.0 ± 19.2 kPa against acrylic substrates. Remarkable adhesion strengths to stainless steel, wood, glass, and polytetrafluoroethylene substrates were also achieved. Due to photo-induced reduction in hydrophilicity of IAP, the polymer was able to repel water at the adhesive–substrate interface upon in situ underwater photocuring, leading to successful wet adhesion. Subsequently, excellent photo-adhesion was also obtained from in situ photocuring of IAP in seawater, simulated body fluid, and silicon oil. This study provides insights into the development of a photo-enhanced and versatile adhesive through green engineering.