Hydrophobization of epoxy nanocomposite surface with 1H,1H,2H,2H-perfluorooctyltrichlorosilane for superhydrophobic properties

Abstract

Nature inspires the design of synthetic materials with superhydrophobic properties, which can be used for applications ranging from self-cleaning surfaces to microfluidic devices. Their water repellent properties are due to hierarchical (micrometer- and nanometre-scale) surface morphological structures, either made of hydrophobic substances or hydrophobized by appropriate surface treatment. In this work, the efficiency of two surface treatment procedures, with a hydrophobic fluoropolymer, synthesized and deposited from 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) is investigated. The procedures involved reactions from the gas and liquid phases of the PFOTS/hexane solutions. The hierarchical structure is created in an epoxy nanocomposite surface, by filling the resin with alumina nanoparticles and micron-sized glass beads and subsequent sandblasting with corundum microparticles. The chemical structure of the deposited fluoropolymer was examined using XPS spectroscopy. The topography of the modified surfaces was characterized using scanning electron microscopy (SEM), and atomic force microscopy (AFM). The hydrophobic properties of the modified surfaces were investigated by water contact and sliding angles measurements. The surfaces exhibited water contact angles of above 150° for both modification procedures, however only the gas phase modification provided the non-sticking behaviour of water droplets (sliding angle of 3°). The discrepancy is attributed to extra surface roughness provided by the latter procedure.

Modification of epoxy resin, silicon and glass surfaces with alkyl- or fluoroalkylsilanes for hydrophobic properties

“…The samples were modified by 1% of silane in cyclohexane solution at room temperature for 30 min. Then, the surfaces were washed out with cyclohexane, dried with nitrogen gas and thermally treated at 40 • C for 24 h. Chemical modification process was carried out according to a procedure developed in our earlier research work [19].…”

Modification of nanostructured fused silica for use as superhydrophobic, IR-transmissive, anti-reflective surfaces

“…[11] However, if the surface is chemically modified with compounds that contain hydrophobic end groups, the surface could then be made to be hydrophobic. [11][12][13][14] In general, surface modified, nanopatterned materials may be useful in numerous field applications such as visible and infrared optical lenses that function in environments where visibility is obstructed due to moisture. Herein we outline a method for the chemical modification of moth eye patterned fused silica for use as self-cleaning, visible and near IR-transmissive, and anti-reflective surface coatings.…”

“…Superhydrophilicity was obtained by forming hydroxyl moieties on the fused silica surfaces via the plasma etch process. Because trichlorosilanes readily form self-assembled monolayers (SAMs) on hydroxyl containing surfaces, the etching process made the surface features more amenable to attachment with the trichlorosilane end of the PFOTS molecule [12]. As a consequence, this aligning of the PFOTS molecule on the surface caused the formation of an array of fluorine molecules (which are on the opposite end of the PFOTS molecule) to interface with the air.…”

Superhydrophobic Surface by Replication of Laser Micromachined Pattern in Epoxy/Alumina Nanoparticle Composite

“…The procedure here is to prepare a rough surface first and then lower its surface energy, by chemical modification. Alkyl and fluoroalkyl chloro/alkoxysilanes or fluoropolymers are the compounds commonly used for surface hydrophobization [8][9][10][11]. The techniques utilized for structure microfabrication include photolithography, nanoimprint lithography, reactive ion etching, chemical etching, soft lithography, anodization, and micro-/nanomachining [4,5,[12][13][14].…”