Mohamed S. Selim

Tailored design of Cu2O nanocube/silicone composites as efficient foul-release coatings

Environmental concerns about the use of toxic antifoulants have increased the demand to develop novel, environmentally-friendly antifouling materials. Silicone coatings are currently the most effective non-toxic alternatives. This study focused on developing a model for silicone foul-release nanocomposites that were successfully designed, fabricated, characterized, and tailored toward foul-release (FR) coatings. A series of elastomeric polydimethyl-siloxane (PDMS)/Cu2O nanocube composites with different nanofiller concentrations was successfully synthesized, for the first time, as FR coatings via solution casting technique. Emphasis was given to the study of the physicomechanical and surface properties, as well as the easy release efficiency of the elastomer PDMS enriched with Cu2O nanocubes. The bulk properties of the nanocomposites appeared unchanged after adding low amounts of nanofillers. By contrast, surface properties such as contact angle and surface free energy were improved, and the settlement resistance and easy release behavior of the nanocomposites were enhanced. The surfaces were further proven to have reversible tunable properties and are thus renewable in water. The antifouling property of the nanocomposites was investigated by laboratory assays involving microfoulants such as Gram-positive and Gram-negative bacteria, as well as yeast organisms, for 30 days. Exposure tests showed that lower surface energy and elastic modulus of coatings resulted in less adherence of marine microfouling. The most profound effect recorded was the reduction of fouling settlement with nanofiller loadings of up to 0.1% Cu2O nanocubes. Thus, the good foul release and long-term durability confirmed that the present strategy was an attractive nontoxic and environmentally-friendly alternative to the existing antifouling systems.

Sunflower oil-based hyperbranched alkyd/spherical ZnO nanocomposite modeling for mechanical and anticorrosive applications

Approaches for designing advanced nanomaterials with hyperbranched architectures and lack of volatile organic content (VOC) have attracted considerable attention. In this study, eco-friendly hyperbranched alkyd resins for mechanical and anticorrosive coatings with high solid content were successfully synthesized based on sunflower oil (SFO) via a polyesterification approach. These resins are characterized by energy-efficient polymer synthesis, lack of gelation properties, high functionality, and low viscosity. A chemical precipitation process was used to fabricate zinc oxide (ZnO) spherical nanostructures with controlled diameters and morphologies. A series of conformal, novel, low-cost SFO-based hyperbranched alkyd/spherical ZnO nanocomposites were fabricated through an ex situ method. Various nanofiller concentrations were distributed to establish synergetic effects on the micro–nano binary scale performance of the materials. The features of the nanocomposites, including the molecular weight, acid and hydroxyl values of the prepared alkyd resins, were concomitantly assessed through various standard tests. The nanocomposites were also subjected to various tests to determine their surface adhesion and mechanical properties, such as impact, T-bending, crosscut, and abrasion resistance tests. Furthermore, the physico-mechanical properties, anticorrosive behavior, thermal stabilities and cellular cytotoxicities of the fabricated materials were assessed. The anticorrosive features of the nanocomposites were investigated through salt spray tests in 5 wt% NaCl. The results indicate that well-dispersed ZnO nanospheres (0.5%) in the interior of the hyperbranched alkyd matrix improve the durability and anticorrosive attributes of the composites; thus, they exhibit potential applications in eco-friendly surface coatings.

Data on photo-nanofiller models for self-cleaning foul release coating of ship hulls.

The data presented in this article are related to the research article entitled “Smart photo-induced silicone/TiO2 nanocomposites with dominant [110] exposed surfaces for self-cleaning foul-release coatings of ship hulls” (Selimet al., 2016) [1]. This article reports on successfully designing and controlling TiO2 spherical single crystal photo-nanofillers and indicating evidence of fouling resistance after stimulation through UV radiation exposure. These data also reveal that the influence of well-dispersed spherical TiO2 nanoparticles (NPs) into the polymer matrix surface features on the prepared fouling release (FR) coating. Single crystal TiO2 nanospheres have played a large role in the scenario of photocatalysis due to its cost effectiveness, inert nature and photo stability. The model output and the surface and mechanical behavior data of the fabricated UV-irradiated silicone-based FR nanocoatings are made publicly available through analyzing nanocomposite topology, superhydrophilicity and self-cleaning efficiency in order to enable critical analysis of the tailored model. It also investigates the photo-bactericidal effect confirmed through biofilm coverage data disability. The modeled nanocomposites were subjected to comparable studies with other published models so as to understand how different UV-irradiated nano-scale parameters propagate and affect bulk film response.

Linseed oil-based alkyd/Cu2O nanocomposite coatings for surface applications

An environment-friendly series of linseed-oil (LO)-based alkyd/Cu2O nanocube nanocomposite coatings was fabricated by a solution-casting method. An easy A2 + B3 approach was used to synthesize a hyperbranched polyester using natural and functional monomers. LO alkyd resin with a hyperbranched architecture was developed by the polyesterification of polyester and unsaturated fatty acids of LO. Hyperbranched alkyd polymers offer many advantages, such as reduced viscosity, multifunctional terminals, and absence of gelation. Controlled synthesis of 60–80 nm Cu2O nanocubes and a cubic morphology was carried out using a wet chemical technique at RT without using any surfactant or template. Different concentrations of single-crystal Cu2O nanocube fillers bound mainly with {100} facets were incorporated into the as-synthesized LO alkyd resin to investigate the effects of nanofiller dispersion on physicomechanical and anticorrosion properties. The surface nonwettability and salt-fog anticorrosive characteristics of the tailored unfilled and alkyd/Cu2O nanocube composites were investigated. Different techniques were used to investigate the composites’ thermal and mechanical features. For all experiments, the maximum improvements in mechanical and anticorrosion properties were achieved by increasing the Cu2O nanofiller loading concentrations up to 0.5%.