title: Fabrication of superhydrophobic copper surface on various substrates for roll-off, self-cleaning, and water/oil separation.
abstract: Superhydrophobic surfaces prevent percolation of water droplets and thus render roll-off, self-cleaning, corrosion protection, etc., which find day-to-day and industrial applications. In this work, we developed a facile, cost-effective, and free-standing method for direct fabrication of copper nanoparticles to engender superhydrophobicity for various flat and irregular surfaces such as glass, transparency sheet (plastic), cotton wool, textile, and silicon substrates. The fabrication of as-prepared superhydrophobic surfaces was accomplished using a simple chemical reduction of copper acetate by hydrazine hydrate at room temperature. The surface morphological studies demonstrate that the as-prepared surfaces are rough and display superhydrophobic character on wetting due to generation of air pockets (The Cassie-Baxter state). Because of the low adhesion of water droplets on the as-prepared surfaces, the surfaces exhibited not only high water contact angle (164 ± 2°, 5 μL droplets) but also superb roll-off and self-cleaning properties. Superhydrophobic copper nanoparticle coated glass surface uniquely withstands water (10 min), mild alkali (5 min in saturated aqueous NaHCO3 of pH ≈ 9), acids (10 s in dilute HNO3, H2SO4 of pH ≈ 5) and thiol (10 s in neat 1-octanethiol) at room temperature (25-35 °C). Again as-prepared surface (cotton wool) was also found to be very effective for water-kerosene separation due to its superhydrophobic and oleophilic character. Additionally, the superhydrophobic copper nanoparticle (deposited on glass surface) was found to exhibit antibacterial activity against both Gram-negative and Gram-positive bacteria.
authors.affiliation: Department of Chemistry and ‡Department of Biotechnology, Indian Institute of Technology , Kharagpur-721302, India.
authors.forename: Anup Kumar
authors.initials: AK
authors.lastname: Sasmal
authors.forename: Chanchal
authors.initials: C
authors.lastname: Mondal
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Sinha
authors.forename: Samiran Sona
authors.initials: SS
authors.lastname: Gauri
authors.forename: Jaya
authors.initials: J
authors.lastname: Pal
authors.forename: Teresa
authors.initials: T
authors.lastname: Aditya
authors.forename: Mainak
authors.initials: M
authors.lastname: Ganguly
authors.forename: Satyahari
authors.initials: S
authors.lastname: Dey
authors.forename: Tarasankar
authors.initials: T
authors.lastname: Pal
mesh_terms: D000268:Adhesiveness; D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D018407:Bacterial Physiological Phenomena / Q000187:drug effects; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology*; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry* / Q000648:ultrastructure; D009821:Oils / Q000737:chemistry* / Q000302:isolation & purification; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D009821:Oils; D014867:Water; D003300:Copper
keywords: contact angle; copper; kerosene-water separation; roll-off; self-cleaning; superhydrophobicity