Role of Backbone versus Catechol Hydrophobicity in removing Interfacial Water

Adhering to surfaces underwater has been a challenge since decades. The marine life such as sand worm castle, barnacles and mussels has taught researchers strategies to remove interfacial water and get hold of surfaces. Mussels use their foot-proteins, i.e., rich in catechol units to bind to different surface chemistries underwater. This observation stimulated the synthesis of catechol-based adhesives which are shown to adhere to all kind of surfaces underwater in literature. However, recently with controlled experiments, researchers have argued and pointed towards the role of backbone hydrophobicity in removing the interfacial water. Even though, the community has a consensus on the role of catechol hydroxyl groups in underwater adhesion, the driver for removal of water from different surfaces is still unknown/debated. In this work, we perform molecular dynamics simulations of catechol based underwater adhesives on self-assembled monolayers and metal oxide surfaces. We will discuss the water structure and the potential required to remove water from vicinities of different groups which expectantly will demarcate the backbone versus catechol hydrophobicity.