title: The effect of composition and thermodynamics on the surface morphology of durable superhydrophobic polymer coatings.
abstract: Durable superhydrophobic coatings were synthesized using a system of silica nanoparticles (NPs) to provide nanoscale roughness, fluorosilane to give hydrophobic chemistry, and three different polymer binders: urethane acrylate, ethyl 2-cyanoacrylate, and epoxy. Coatings composed of different binders incorporating NPs in various concentrations exhibited different superhydrophobic attributes when applied on polycarbonate (PC) and glass substrates and as a function of coating composition. It was found that the substrate surface characteristics and wettability affected the superhydrophobic characteristics of the coatings. Interfacial tension and spreading coefficient parameters (thermodynamics) of the coating components were used to predict the localization of the NPs for the different binders' concentrations. The thermodynamic analysis of the NPs localization was in good agreement with the experimental observations. On the basis of the thermodynamic analysis and the experimental scanning electron microscopy, X-ray photoelectron spectroscopy, profilometry, and atomic force microscopy results, it was concluded that localization of the NPs on the surface was critical to provide the necessary roughness and resulting superhydrophobicity. The durability evaluated by tape testing of the epoxy formulations was the best on both glass and PC. Several coating compositions retained their superhydrophobicity after the tape test. In summary, it was concluded that thermodynamic analysis is a powerful tool to predict the roughness of the coating due to the location of NPs on the surface, and hence can be used in the design of superhydrophobic coatings.
authors.affiliation: Department of Plastics Engineering, University of Massachusetts Lowell, Lowell, MA, USA.
authors.forename: Tehila
authors.initials: T
authors.lastname: Nahum
authors.affiliation: Department of Polymers and Plastics Engineering, Shenkar College of Engineering Design and Art, Ramat Gan, Israel.
authors.forename: Hanna
authors.initials: H
authors.lastname: Dodiuk
authors.affiliation: Department of Polymers and Plastics Engineering, Shenkar College of Engineering Design and Art, Ramat Gan, Israel.
authors.forename: Samuel
authors.initials: S
authors.lastname: Kenig
authors.affiliation: Department of Plastics Engineering, University of Massachusetts Lowell, Lowell, MA, USA.
authors.forename: Artee
authors.initials: A
authors.lastname: Panwar
authors.affiliation: Department of Plastics Engineering, University of Massachusetts Lowell, Lowell, MA, USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Barry
authors.affiliation: Department of Plastics Engineering, University of Massachusetts Lowell, Lowell, MA, USA.
authors.forename: Joey
authors.initials: J
authors.lastname: Mead
keywords: durability; morphology; silica nanoparticles; superhydrophobic coating; thermodynamics