Superhydrophobic Silicone/TiO₂–SiO₂ Nanorod‐like Composites for Marine Fouling Release Coatings

Abstract

For the first time, a superhydrophobic series of silicone/nanorod‐like TiO2–SiO2 core–shell composites was fabricated by solution casting for marine fouling release (FR) coatings. Hydrothermal technique was used to prepare single crystal TiO2 nanorods as a core structure in the diameter regime of 20 nm and preferentially grown in {101} direction. Hybrid nanorod‐like TiO2–SiO2 core–shell nanofillers were synthesized by sol–gel technique with silica shell thickness of 2–5 nm. The structure‐property relationship was investigated by dispersing various nanofiller concentrations in the silicone matrix. Surface non‐wettability properties were investigated using water contact angle (WCA), surface free energy (SFE), and atomic force microscopy. Coating′s photocatalytic degradation of organic pollutants and microorganisms was also investigated. Selected micro‐ and macro‐fouling strains were used for antifouling assessments in laboratory. The fabricated models were subjected to a rigorous field trial in natural seawater for 6 months in a tropical area. Well‐distributed nanorod‐like TiO2–SiO2 core–shell (0.5 wt.%) exhibited the preferable FR self‐cleaning with WCA of 154° and SFE of 10.45 mN/m.

Yolk–Shell Nanostructures: Syntheses and Applications for Lithium-Ion Battery Anodes

“…Thus, the authors adopted the yolk-shell architecture as an appropriate nanoreactor for the catalytic reaction since the titania shell can isolate the gold nanoparticles from clustering and guarantee the transfer of gases in and out of the inner space for sufficient access to gold surfaces. Typical materials for templating are silica, carbon, metal, metal oxides, and oligomers [32,33]. Silica is one of the most frequently used hard templates for the fabrication of yolk-shell nanostructures due to its easy removal with alkali or hydrogen fluoride treatment.…”

Superhydrophobic Self-cleaning Surfaces in Nature

“…Moreover, the International Maritime Organization (IMO, 2003) banned the use of tinrelated compounds for fouling resistance on ship hull coatings. The worldwide ban accompanied by utilizing toxic antifouling paints have driven modern research toward eco-friendly solutions particularly, FR technology [61][62][63][64][65][66][67] . Controlling the size and morphology of nanomaterials can improve the performance of nanocomposite [68][69][70] .…”

“…FR self-cleaning, mechanical durability, cost-savings are characteristics provided by PDMS nanocomposite coatings as organic/inorganic hybrids [77][78][79][80][81] . Selim et al projected a superior trend of TiO 2 @SiO 2 core-shell enriched in silicone composites as smart photo-induced FR nanopaints (Figure 7) [64] . Contact angle test was performed on a series of nanocomposites prepared through different nanofiller percentages; where high self-cleaning effect was reflected for the well-dispersed nanocomposite (0.5 wt.% nanofiller concentration).…”

“…Contact angle test was performed on a series of nanocomposites prepared through different nanofiller percentages; where high self-cleaning effect was reflected for the well-dispersed nanocomposite (0.5 wt.% nanofiller concentration). High fouling-resistance for the well-dispersed sample was illustrated through bacterial antiadhesion mechanism [64] .…”

Transparent and Self‐Cleaning Surfaces Based on Nanocomposite Sol‐Gel Coatings

“…Superhydrophobic surfaces can be produced via two strategies: (1) designing ultra-smooth surfaces; and (2) modifying rough surfaces, both based on low-surface-energy materials. [2,3,[3][4][5]5,6] Superhydrophilic surfaces can be referred to those textured and/or structured materials having a surface roughness factor (as defined in the Wenzel equation) greater than one, r > 1, on which water spreads completely and then form water across layer i. e. water would lie on such a surface as a flat film rather than in form of droplets, and hence the dirt, dust and other staining materials on the surface can be readily washed away with this super-spreading water layer. [7] The wettability of such surface is dependent on its surface free energy and surface geometrical structure.…”