Brush swelling and attachment strength of barnacle adhesion protein on zwitterionic polymer films as a function of macromolecular structure

The exceptional hydration of sulfobetaine polymer brushes and their resistance towards non-specific protein absorption allows for the construction of thin films with excellent anti-biofouling properties. In this work, swollen sulfobetaine brushes, prepared by SI-ATRP of two monomers, differentiated by the nature of the polymerizable group, are studied and compared by using liquid-cell Atomic force Microscopy (AFM) technique and spectroscopic ellipsometry (SE). Colloidal AFM based force spectroscopy is employed to estimate brush grafting density and characterize nanomechanical properties in salt water. When the ionic strength induced swelling behavior of the two systems are compared, the differences observed on the anti-polyelectrolyte response can be correlated with the stiffness variation on brush compression, likely to be promoted by solvation differences. The higher solvation of amide groups is proposed to be responsible for the lower adhesion force of barnacle cyprid’s temporary adhesive proteins. The...