Understanding the surface properties of polybenzoxazines: Interaction of polybenzoxazine model compounds with metal ions and water

The structure of polybenzoxazines (and their properties) is mainly defined by the existence of intra‐ and intermolecular hydrogen bonds. The effect of different substituents present in the phenolic ring of polybenzoxazines can modulate these intermolecular forces and the interaction with other materials, such as metals. To extend this knowledge, a series of structure‐controlled polybenzoxazines and polybenzoxazine model compounds have been synthesized. The interactions with different metal ions have been investigated using UV–vis and NMR analysis. Association constants have been estimated by UV–vis titration method and the effect of the presence of different substituents in the aromatic ring has been established. Water contact angles have also been measured. The different techniques give us information about the inner hydrogen bonding structure. Cyano group, present as substituent in polybenzoxazine compounds, acts as an additional coordination point towards metal ions and water. Our findings should allow modulating the adhesion and other surface properties of the benzoxazine‐derived polymers by playing with the properties of the substituents and their structure (phenoxy/phenolic).