Sequence of Hydrophobic and Hydrophilic Residues in Amphiphilic Polymer Coatings Affects Surface Structure and Marine Antifouling/Fouling Release Properties.

Abstract

Amphiphilic polymers, specifically combinations of hydrophilic and hydrophobic residues, have been shown to be effective as antifouling materials against the algae Ulva linza and Navicula diatoms. Here we use the inherent sequence specificity of polypeptoids made by solid-phase synthesis to show that the sequence of hydrophilic (methoxy) and hydrophobic (fluorinated) moieties affects both antifouling and fouling release of U. linza. The platform used to test these sequences was a polystyrene-b-poly(ethylene oxide-co-allyl glycidyl ether) (PS-b-P(EO-co-AGE)) scaffold, where the polypeptoids are attached to the scaffold using thiol-ene click chemistry. The fluorinated moiety is very surface active and directs the surface composition of the polymer thin film. The position and number of fluorinated groups in the polypeptoid are shown to affect both the surface composition and antifouling properties of the film. Specifically, the position of the fluorinated units in the peptoid chain changes the surface chemistry and the antifouling behavior, while the number of fluorinated residues affects the fouling-release properties.