Mussel-inspired novel high adhesive UV-curable polyurethane/polysiloxane pressure sensitive adhesive

Biomaterials provide inspiration for the assembly of preparation molecules into complex structures. There is more catecholic amino acid dihydroxyphenylalanine in mussel's holdfasts, which is beneficial to enhance the interfacial adhesion to the marine surfaces. Although there are numerous scholars on mussel-mimicking polymers, there are still insufficient researches on structure-property relations, especially on the effect of carboxyl structure on polymer properties. Inspired by this, the monomers with different carboxyl functional groups are synthesized in this report. A series of pressure sensitive adhesives (PSAs) are feasibly tailored by introducing the novel monomers (MCA, MCAB, MCAP) into PSAs through photo-polymerization. The effect of benzene monomers with different carboxyl groups on the adhesive properties of the PSAs is further studied. The results show that with the increase of carboxyl groups on the benzene ring, the 180° peel strength and shear strength of PSAs (SPU-8-MCAP) are increased by 180.0% and 46.2%, respectively. Additionally, the heat resistance and carbon residue rate of PSAs have also been improved, mainly due to the introduction of carboxyl groups to strengthen the intermolecular or intramolecular interactions. Density functional theory (DFT) proves that the increase of carboxyl group content is indeed beneficial to strengthen the interaction between molecules. It is anticipated that these studies will contribute to the design of future biomimetic systems and promote the progress of carboxyl monomers in adhesives.