Fluorine Based Superhydrophobic Coatings

Abstract

Superhydrophobic coatings, inspired by nature, are an emerging technology. These water repellent coatings can be used as solutions for corrosion, biofouling and even water and air drag reduction applications. In this work, synthesis of monodispersive silica nanoparticles of ~120 nm diameter has been realized via Stöber process and further functionalized using fluoroalkylsilane (FAS-17) molecules to incorporate the fluorinated groups with the silica nanoparticles in an ethanolic solution. The synthesized fluorinated silica nanoparticles have been spin coated on flat aluminum alloy, silicon and glass substrates. Functionalization of silica nanoparticles with fluorinated groups has been confirmed by Fourier Transform Infrared spectroscopy (FTIR) by showing the presence of C-F and Si-O-Si bonds. The water contact angles and surface roughness increase with the number of spin-coated thin films layers. The critical size of ~119 nm renders aluminum surface superhydrophobic with three layers of coating using as-prepared nanoparticle suspended solution. On the other hand, seven layers are required for a 50 vol.% diluted solution to achieve superhydrophobicity. In both the cases, water contact angles were more than 150°, contact angle hysteresis was less than 2° having a critical roughness value of ~0.700 µm. The fluorinated silica nanoparticle coated surfaces are also transparent and can be used as paint additives to obtain transparent coatings. OPEN ACCESSAppl. Sci. 2012, 2 454

Nano-micro structured superhydrophobic zinc coating on steel for prevention of corrosion and ice adhesion

“…(3). Brassard et al [38] previously showed with a model that the fluorinated silica nanoparticles also follows the Cassie-Baxter model [31]. They have shown the roughness of the silica nanoparticle films is proportional to the air fraction and that water contact angle increases with the increase of the roughness of the films due to the increase of the silica nanoparticles.…”

“…The manufacturer of the RTV silicone specified that it contains mainly three different molecules: trimethoxymethylsilane, hexamethyldisilazane and octamethylcyclotetrasiloxane. The peaks at 800 and 1100 cm −1 correspond to the asymmetric stretching vibration of Si-O-Si group [38] and [42]. A peak approximately at −1 is due to the Si-O-C bond.…”

“…Two peaks at 1150 and 910 cm −1 are due to Si-N bondings [43]. The peaks at 1400, 2950 and 3000 cm −1 were assigned to -CH3 [38] and [42] as silicone contains plenty of methylated groups (-CH3). The presence of -CH3 as well as -CH2 together reduces the surface energy and enhances the water contact angle to a surface that leads to the superhydrophobic properties.…”

Superhydrophobic Surfaces Created by Elastic Instability of PDMS

“…Various approaches have been used to modify the surfaces of PDMS, including: chemical methods [9][10][11] and physical methods, such as ultraviolet ozone [12], and oxygen plasma [8,13]. In this paper, we used molding in order to reach the required roughness.…”

Synthesis of some new fluorine substituted thiobarbituric acid derivatives as anti HIV1 and cyclin-dependent kinase 2 (CDK2) for cell tumor division: Part I

“…The introduction of fluorine atoms to bioactive molecules enhance and improve their pharmacological properties [16][17][18]. Also, presence of hetero-atoms increased membrane, permeability, which enhances the electrostatic force and hydrophobic binding stability against metabolic transformations [18][19][20][21][22]. As part of the interested research program in the fluorine substituted heterocyclic nitrogen systems as biocidal agents [23][24][25][26][27], the present work tends to synthesize, some new fluorinated-thiobarbituric acids full fused in view of their anti-HIV and cyclin-dependent kinase 2.…”