Surface Segregation of Amphiphilic PDMS-Based Films Containing Terpolymers with Siloxane, Fluorinated and Ethoxylated Side Chains

Abstract

(Meth)acrylic terpolymers carrying siloxane (Si), fluoroalkyl (F) and ethoxylated (EG) side chains were synthesized with comparable molar compositions and different lengths of the Si and EG side chains, while the length of the fluorinated side chain was kept constant. Such terpolymers were used as surface-active modifiers of polydimethylsiloxane (PDMS)-based films with a loading of 4 wt%. The surface chemical compositions of both the films and the pristine terpolymers were determined by angle-resolved X-ray photoelectron spectroscopy (AR-XPS) at different photoemission angles. The terpolymer was effectively segregated to the polymer−air interface of the films independent of the length of the constituent side chains. However, the specific details of the film surface modification depended upon the chemical structure of the terpolymer itself. The exceptionally high enrichment in F chains at the surface caused the accumulation of EG chains at the surface as well. The response of the films to the water environment was also proven to strictly depend on the type of terpolymer contained. While terpolymers with shorter EG chains appeared not to be affected by immersion in water for seven days, those containing longer EG chains underwent a massive surface reconstruction.

Amphiphilic Polyphosphonate Copolymers as New Additives for PDMS-Based Antifouling Coatings

“…This class of hydrophilic polymers could offer an attractive alternative to polyethylene glycol (PEG) and polyzwitterions, as PPEs are not plagued by uncontrolled oxidative degradation. In particular, aiming to intrinsically benign, biocide-free antifouling (AF) and fouling-release (FR) surfaces, in the last years much effort was devoted to the design of coatings with optimal performance achieved through several approaches, centered on tuning morphology, topography, surface reconstruction, segregation, and wettability of polymer films [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Particularly promising, the FR approach relies on the combination of low surface energy, low elastic modulus, and low surface roughness typical of polydimethylsiloxanes [ 23 , 24 , 25 , 26 ], facilitating the release of the fouling biomass in presence of relatively low hydrodynamic forces, e.g., the shear stress induced on ship hulls during navigation.…”

The Effect of Poly(ethylene glycol) (PEG) Length on the Wettability and Surface Chemistry of PEG-Fluoroalkyl-Modified Polystyrene Diblock Copolymers and Their Two-Layer Films with Elastomer Matrix

“…The use of amphiphilic polymer surface active-additives, derived from the combination of hydrophilic and hydrophobic components in the same macromolecular structure, has gained interest in recent decades as a straightforward and useful strategy to tailor surface- and interface-structuring factors of wettability, reconstruction, morphology and topography at the nanoscale of polymer films [ 17 , 18 , 34 , 35 ]. In particular, amphiphilic surface-active additives, composed of polysiloxane and/or fluoropolymer chains as the hydrophobic components, and poly(ethylene glycol) (PEG) chains as the hydrophilic components, have been investigated in different fields of nanotechnology [ 3 , 34 , 36 , 37 , 38 , 39 ]. The self-assembly of such amphiphilic copolymers in fact is also possible in the bulk copolymer itself [ 40 , 41 ], or when dissolved in a selective solvent, determining a variety of nanostructures ranging from single chain nanoparticles to large aggregates [ 42 , 43 , 44 , 45 , 46 ].…”

Polyethylene Glycol-b-poly(trialkylsilyl methacrylate-co-methyl methacrylate) Hydrolyzable Block Copolymers for Eco-Friendly Self-Polishing Marine Coatings

“…After the international ban of tributyltin (TBT)-based self-polishing coatings (SPCs) in 2008, the two most effective antifouling (AF) technologies actually present on the market for the marine shipping industries are nontoxic fouling-release coatings (FRCs) which are able to promote the detachment of eventually settled foulers under the action of relatively low shear stresses, and self-polishing coatings (SPCs), which act on marine organisms by inhibiting or limiting their settlement using the release of biocides embedded or linked to a polymer matrix [ 1 , 2 , 3 , 4 , 5 , 6 ]. The former coatings are mainly based on poly(dimethylsiloxane) (PDMS) elastomer matrixes containing amphiphilic surface-active (co)polymers [ 7 , 8 , 9 , 10 , 11 ], and as a result of their surface segregation promote the hydrophilization of the PDMS surface, thus enhancing its AF performance in static conditions and against microfouling [ 11 , 12 , 13 , 14 , 15 , 16 ]. These coatings have been widely investigated [ 9 , 17 , 18 , 19 ] and currently have a modest market share, especially because of the higher cost and lower efficiency of static conditions compared with traditional SPCs.…”