Browsing by Subject "Superhydrophobic surfaces"
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Item Open Access Antifouling superhydrophobic surfaces with bactericidal and SERS activity(Elsevier BV, 2022-03-01) Şahin, F.; Çelik, N.; Ceylan, A.; Pekdemir, S.; Ruzi, M.; Önses, Mustafa SerdarFouling and contamination of surfaces are prevailing challenges humanities facing today in fields such as healthcare, hospitality, and food manufacturing. These challenges strongly motivate the development of multifunctional surfaces with antifouling and antimicrobial properties that are coupled with sensing capabilities. To address this challenge, we prepared a multifunctional superhydrophobic surface using eco-friendly materials: polydimethylsiloxane (PDMS) and carnauba wax. After deposition of a thin film of Ag, the surface gained surface-enhanced Raman scattering (SERS) activity and bactericidal property. The multifunctional superhydrophobic surface showed extreme liquid repellency towards water and common liquid food. The strong SERS activity enabled the detection of adulterant rhodamine B in a sausage down to a nanomolar level. Notably, the surface showed excellent bactericidal activity towards two common bacteria, E. coli, and S. aureus, significantly reducing their adhesion and killing. Additionally, the surface showed anti-fouling behavior against common liquid food, and even towards sticky foods such as yogurt, honey, and pomegranate sauce, reducing residual food by >97 %. Furthermore, the superhydrophobic surface showed excellent chemical stability in dynamic and static flow conditions and leaching of Ag in neutral and basic solutions was minimal.Item Embargo Fully transparent and superhydrophobic electrodes enabled by soft interfaces(Elsevier BV, 2022-12-16) Torun, İ.; Çelik, N.; Kiremitler, N. B.; Huang, X.; Önses, Mustafa SerdarThe simultaneous achievement of transparency, electrical conductivity and superhydrophobicity is a highly challenging and rewarding task for a range of technological applications. This manuscript reports a practical and fluorine-free approach for fully transparent and superhydrophobic coatings on a transparent electrode. The first step consists of the formation of a grafted film of poly(ethylene glycol) on an indium oxide coated glass substrate. The superhydrophobicity is then achieved by spray-coating a film of alkylsilane functionalized nanoparticles. The self-assembly of the hydrophobic nanoparticles on end-grafted poly(ethylene glycol) allows for controlled formation of roughness without sacrificing the transparency and electrical conductivity. The result is a multi-functional substrate with a static contact angle of 172°, sliding angle of 1°, 90.4% transparency at a wavelength of 550 nm, and a sheet resistance of 13.05 Ω/sq. The surface has high water impact-resistance and thermal stability provided by the soft-interface composed of end-grafted poly(ethylene glycol). The reported substrate exhibits outstanding figures of merit in terms of the water repellency, optoelectronic performance, and stability. Application in transparent heaters demonstrates the promise of the presented multi-functional coatings.Item Open Access Sustainable and practical superhydrophobic surfaces via mechanochemical grafting(John Wiley and Sons Inc, 2023-05-25) Çelik, N.; Akay, S.; Şahin, F.; Sezer, G.; Dağaşan Bulucu, E.; Ruzi, M.; Butt, H.-J.; Önses, Mustafa SerdarThe broad adoption of superhydrophobic surfaces in practical applications is hindered by limitations of existing methods in terms of excessive usage of solvents, the need for tedious and lengthy chemical processes, insufficient biocompatibility, and the high cost of materials. Herein, a mechanochemical approach for practical and solvent-free manufacturing of superhydrophobic surfaces is reported. This approach enables solvent-free and ultra-rapid preparation of superhydrophobic surfaces in a single-step without the need for any washing, separation, and drying steps. The hydrolytic rupture of siloxane bonds and generation of free radicals induced by mechanochemical pathways play a key role in covalent grafting of silicone to the surface of nanoparticles that leads to superhydrophobic surfaces with a water contact angle of >165° and a sliding angle of <2°. The direct use of industrially available and non-functional silicone materials together with demonstrated applicability to inorganic nanoparticles of varied composition greatly contribute to the scalability of the presented approach. The resulting superhydrophobic surfaces are highly biocompatible as demonstrated by fibroblast cells using two different assays. Monolith materials fabricated from silicone-grafted nanoparticles exhibit bulk and durable superhydrophobicity. The presented approach offers tremendous potential with sustainability, scalability, cost-effectiveness, simplicity, biocompatibility, and universality.Item Open Access Waxing the soot: Practical fabrication of all-organic superhydrophobic coatings from candle soot and carnauba wax(Elsevier, 2021-02-04) Celik, N.; Celik, N. B.; Ruzi, M.; Önses, Mustafa SerdarCommercial application of superhydrophobic coatings is hindered by insufficient durability and use of materials with high costs and limited availability. In this study, we report a robust water impact resistant all-organic superhydrophobic coating that is prepared from low-cost colloidal dispersion composed of carnauba wax and candle soot. The colloidal dispersion is stable and can be spray-coated onto virtually any surfaces. The coated surfaces exhibit superhydrophobicity with a water contact angle of 172° and sliding angle of 3°, and retain superhydrophobicity even after 400 cycles of continuous water spray with an impact pressure of 7.4 kPa. The synergetic combination of candle soot and carnauba wax, together with the deposition method, solvent used to disperse materials, and spray-coating distance are critically important for the superhydrophobicity and mechanical durability. The robustness of the coatings emerges from the two-tier hierarchical structure of the dried particles which is formed by evaporation induced self-assembly of wax molecules and candle soot nanoparticles. Applications in self-cleaning and oil/water separation are demonstrated, where a coated membrane can be continuously operated, solely driven by gravity, and can separate common organic liquids such as hexane and toluene from water with a separation efficiency of more than 90 % at a high flux of 1061 L / (m2 h).