Layer-by-Layer Deposited Hybrid Polymer Coatings Based on Polysaccharides and Zwitterionic Silanes with Marine Antifouling Properties.

Polyelectrolyte multilayer (PEM) assembly is a versatile tool to construct low-fouling coatings. For application in the marine environment, their structure needs to be stabilized by covalent linkage. Here, we introduce an approach for spin coating of silane-based sol-gel chemistries using layer-by-layer assembly of polysaccharide-based hybrid polymer coatings (LBLHPs). The silane sol-gel chemistry allows the films to be cross-linked under water-based and mild reaction conditions. Two different silanes were used for this purpose, a conventional triethoxymethyl silane and a de novo synthesized zwitterionic silane. The polysaccharide-silane hybrid polymer coatings were thoroughly characterized with spectroscopic ellipsometry, water contact angle (WCA) goniometry, attenuated total reflection-Fourier transform infrared spectroscopy, and atomic force microscopy. The coatings showed good stability in seawater, smooth surfaces, a high degree of hydration, and WCAs below or close to the Berg limit. LBLHPs showed low-fouling properties in biological assays against nonspecific protein adsorption, attachment of the diatom Navicula perminuta , and settlement of zoospores of the macroalga Ulva linza .