The Role of Hydrogen Bonding in Peptoid-Based Marine Antifouling Coatings

Abstract

The benefits of incorporating amphiphilic properties into antifouling and fouling-release coatings are well-established. The use of sequence-defined peptides and peptoids in these coatings allows precise control over the spacing and chemistry of the amphiphilic groups, but amphiphilic peptoids have generally outperformed analogous peptides for reasons attributed to differences in backbone structure. The present work demonstrates that the superior properties of peptoids relative to peptides are primarily attributable to a lack of hydrogen bond donors rather than to their secondary structure. A new amphiphilic peptoid was designed containing functional groups similar to those typically found on a hydrogen-bonding peptide backbone. This peptoid and a non-hydrogen-bonding peptoid analogue were incorporated as side chains in PDMS-based polymer scaffolds. Bioassays with the soft algal fouling organisms Ulva linza and Navicula incerta indicate that hydrogen bonding largely determines the differences seen between similar peptide and peptoid species, while sum frequency generation vibrational spectroscopy suggests that the presence of hydrogen bond donors enhances interfacial water structuring. This reduced initial U. linza adhesion, but attached algae were more strongly bound by hydrogen-bonding interactions. Consequently, amphiphilic peptoid materials lacking hydrogen bond donors are better suited to resist marine fouling, with enhanced release of U. linza and similar performance against N. incerta relative to hydrogen-bonding analogues.

Surface hydration for antifouling and bio-adhesion

“…11,[46][47][48][49][50][51] It was found in our previous research that stronger surface hydration leads to better antifouling behavior. [10][11][12][13]52,53 The strong hydration is characterized by a strong 3200 cm À1 peak, a weak (or absence of) 3400 cm À1 signal, and a strong overall water signal intensity. [10][11][12][13] For example, SFG spectra collected from the antifouling SBMA and OEGMA surfaces in water are both dominated by the $3200 cm À1 peak, showing that the surfaces are covered by strongly bonded water molecules, leading to excellent antifouling properties.…”

New Approaches to EUV Photoresists: Studies of Polyacetals and Polypeptoids to Expand the Photopolymer Toolbox

“…In a second resist material, we explore the construction of polymers derived from peptoid units [6]. This polymer family, prepared using a robot synthesizer system originally developed for protein synthesis, is produced on a polymer substrate and can be made in gram quantities.…”

Polymeric Coatings Based on Water-Soluble Trimethylammonium Copolymers for Antifouling Applications

“…The most widely used materials for FR coatings are based on polydimethylsiloxane (PDMS) and fluorinated materials [8][9][10][11]. However, due to the fact that these coatings suffer from several disadvantages, they are usually combined with hydrophilic components leading to amphiphilic surfaces with improved performance [12,13].…”