Effects of surface-active block copolymers with oxyethylene and fluoroalkyl side chains on the antifouling performance of silicone-based films

Abstract

Block copolymers made from a poly(dimethyl siloxane) (Si) and a poly(meth)acrylate carrying oxyethylene (EG) or fluoroalkyl (AF) side chains were synthesized and incorporated as surface-active components into a silicone matrix to produce cross-linked films with different surface hydrophilicity/phobicity. Near-edge X-ray absorption fine structure (NEXAFS) studies showed that film surfaces containing Si-EG were largely populated by the siloxane, with the oxyethylene chains present only to a minor extent. In contrast, the fluorinated block was selectively segregated to the polymer-air interface in films containing Si-AF as probed by NEXAFS and X-ray photoelectron spectroscopy (XPS) analyses. Such differences in surface composition were reflected in the biological performance of the coatings. While the films with Si-EG showed a higher removal of both Ulva linza sporelings and Balanus amphitrite juveniles than the silicone control, those with Si-AF exhibited excellent antifouling properties, preventing the settlement of cyprids of B. amphitrite.

Amphiphilic Polymer Platforms: Surface Engineering of Films for Marine Antibiofouling

“…Secondly, the surface‐active copolymer that more effectively limited the attachment or promoted the release of U. linza was the fluorine‐free amphiphilic copolymer, containing only the polysiloxane and PEG side chains. Similar results were obtained when the FR performance against U. linza of two different surface‐active copolymers composed of the same PDMS block and a different poly(meth)acrylate block carrying PEG or perfluorohexylethyl side chains were compared . The fluorine‐free amphiphilic block copolymers showed a higher removal of sporelings with respect to the fluorinated block copolymers.…”

Model Amphiphilic Block Copolymers with Tailored Molecular Weight and Composition in PDMS-Based Films to Limit Soft Biofouling

“…Recent work utilized siloxane block copolymers with either a fluoroalkyl-containing or a PEG-containing block as additives to a PDMS network. 49 While this showed that fluoroalkyl and PEG chain groups acted independently, our goal was to ascertain whether combining these functionalities into one block copolymer could provide additional synergistic benefits of both groups in one film. It has been hypothesized that the combination of polar (PEG) and non-polar (fluoroalkyl/PDMS) units 4 creates an "ambiguous" surface, in which the fouling species encounters a surface that spontaneously alternates between polar and non-polar character.…”

The self‐assembly over nano‐ to submicro‐length scales in water of a fluorescent julolidine‐labeled amphiphilic random terpolymer

“…However, the more marked hydrophobic nature of the FA co‐units of the latter leads to a lower T c than that reported for the corresponding homopolymer (∼66 °C) . The inclusion of low surface energy fluoroalkyl side chains in a polymer structure is, in fact, known to drastically enhance the hydrophobic and lipophobic nature of the entire system which results in a strong capability to self‐assemble in solution, in bulk and at the surface of thin films …”