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Keywords:

  • marine biofouling;
  • polymer brushes;
  • hydrophilic polymers

Abstract

Polymeric ultrathin films present a possible line of attack against marine biofouling for some applications. A protocol that provides a reliable comparison of the resistance of different polymers to biofouling is described. This is achieved through the use of a common, azide-terminated adhesion monolayer, to which different nonfouling polymers of various molecular weights, specifically poly(ethylene glycol) (PEG), poly(2-ethyl-2-oxazoline) (PEOXA), poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA), and dextran are covalently bound. These functionalized surfaces are characterized by dynamic contact angle, ellipsometry, and X-ray photoelectron spectroscopy (XPS). To validate the developed protocol and evaluate performance against a selection of well-known, marine-fouling organisms, the nonfouling surfaces are subjected to a comparative biological study by exposure to a complex protein solution (with characterization via ellipsometry and quartz crystal microbalance with dissipation (QCM-D)), marine bacteria (Cobetia marina and Marinobacter hydrocarbonoclasticus), and zoospores of the green alga Ulva linza. The resulting data are used to draw conclusions on structure-property relationships. Chemical resistance towards marine fouling can be achieved using the described immobilization method, but is highly dependent on the species tested. Findings show that PVP (55 kDa)-coated surfaces display consistent resistance towards all tested solutions and organisms and, hence, this polymer could be considered as a potential material for marine-nonfouling applications.