Adhesion and Cohesion Differences between Catechol‐ and Pyrogallol‐Functionalized Chitosan

Abstract

Marine‐inspired phenolic compounds that exhibit underwater adhesion are used as biomedical adhesives under wet conditions. While these applications mainly use catechol and pyrogallol moieties that contain different numbers of hydroxyl groups on their benzene rings, how this difference affects adhesion and cohesion is not well understood. Herein, the chitosan backbone is functionalized with catechol and pyrogallol at similar modification rates (to give chitosan‐catechol (CS‐CA) and chitosan‐pyrogallol (CS‐GA), respectively) and their interaction energies are compared by using a surface forces apparatus (SFA). The phenolic moieties decrease the rigidity of the chitosan chain and increase solubility; consequently, CS‐CA and CS‐GA are more cohesive and adhesive than chitosan at pH 7.4. Moreover, the additional hydroxyl group of GA provides a further interacting chance; hence, CS‐GA is more cohesive and adhesive than CS‐CA. This study provides in‐depth insight into interactions involving chitosan derivatives bearing introduced phenolic moieties that will help to develop biomedical adhesives.

A comprehensive study on rheological properties of photocrosslinkable gallol-metal complexed hyaluronic acid-based biomaterial inks

“…It is important to note that three hydroxyl groups on the benzene ring of gallol interact with metal ions better than DOPA (two hydroxyl groups), leading to a stronger cohesive force between a polymeric network of hydrogels due to hydrogen bond formation and a metal complex. 46 Due to their self-healing properties, the irregular filaments produced by HAMA–GA 0.125Fe returned to their original moduli after printing, ultimately forming a smooth printed tubular structure, as also shown in Fig. S12 (ESI†).…”

Green polyphenol-based photothermal interfacial evaporation systems toward solar water production

“…74 GA has a catechol structure, which provides further interaction opportunities than PDA's catechol structure, so it is more cohesive and adhesive. 75 In addition, its strong adhesion is mainly due to the π-π interaction of the phenol ring, the cation-π bond and the hydrophilic interaction of the hydroxyl group. 74 In recent years, TA based coatings have become the new favorite in the field of interface modification by virtue of their advantages of green safety, low cost and easy preparation.…”

“…74 GA has a catechol structure, which provides further interaction opportunities than PDA's catechol structure, so it is more cohesive and adhesive. 75 In addition, its strong adhesion is mainly due to the π–π interaction of the phenol ring, the cation–π bond and the hydrophilic interaction of the hydroxyl group. 74…”