• surface active polymers
• polyphosphonates
• biofouling

The first part of this thesis work consisted of a review of the literature on poly(phosphoester)-based systems as novel hydrophilic and hydrolysable components for the development of amphiphilic copolymers for anti(bio)fouling applications. The second part was devoted to an experimental work for the synthesis of three different classes of amphiphilic copolymers by alternatively copolymerizing the same hydrophobic polysiloxane methacrylate monomer (SiMA) with three different methacrylate comonomers carrying hydrophilic poly(phophonate) (PHN), zwitterion (MPC) and poly(ethylene glycol) monomethyl ether (PEGMA) side chains. The last was chosen as reference sample as it represents a gold standard for the development of amphiphilic coatings to combat marine biofouling. PHN- and MPC-based copolymers with different chemical compositions, i.e. modulated hydrophilic/hydrophobic balance, were synthesised and their bulk solubility, thermoresponsiveness and thermal properties were evaluated. Moreover, the hydrolysis kinetics of the PHN homopolymer and respective copolymers was investigated in different pH conditions, including those similar to a marine environment.
Three water-insoluble copolymers, containing similar amount of each hydrophilic counits, were incorporated as surface-active additives into condensation-cure matrix films to independently control both the bulk elastomeric mechanical properties and the surface wetting properties. Water contact angle measurements showed that all films were moderately hydrophobic, being the contact angle in the range 100 °- 110 °. However, the film surfaces became more hydrophilic upon prolonged immersion in water. In particular, after 21 days of immersion the films containing the amphiphilic copolymers displayed a decrease in water contact angle with respect to the initial value higher than that typical of the unmodified PDMS film, indicating that amphiphilic films underwent a more marked surface reconstruction than did PDMS. Interestingly, the extent of surface reconstruction appeared to be affected by the type of hydrophilic counits, showing a tendency to increase according to the order PEGMA < MPC < PHN. X-ray photoelectron spectroscopy (XPS) analyses confirmed that the films before immersion in water were predominantly populated by the low surface energy, hydrophobic polysiloxane component and that a week of immersion in water was not enough to detect the presence of the hydrophilic PHN and MPC units at the polymer surface.
Initial biological tests were carried out against two model organisms, namely the serpulid Ficopomatus enigmaticus and the diatom Navicula salinicola. Results suggest that F. enigmaticus tended to adhere strongly to coatings with higher amounts of amphiphilic copolymers. On the other hand, coatings with larger copolymer loadings were found to better inhibit the settlement of N. salinicola, even though more than 90% of the diatoms were successfully removed from all the coatings, including the PDMS control, under the action of a relatively low shear stress of 20 Pa.