Hydrophobic Nanocomposites Research Articles

Organic-Inorganic Hydrophobic Nanocomposite Film with a Core-Shell Structure.

A method to prepare novel organic-inorganic hydrophobic nanocomposite films was proposed by a site-specific polymerization process. The inorganic part, the core of the nanocomposite, is a ternary SiO2–Al2O3–TiO2 nanoparticles, which is grafted with methacryloxy propyl trimethoxyl silane (KH570), and wrapped by fluoride and siloxane polymers. The synthesized samples are characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrscopy, X-ray diffractometry (XRD), contact angle meter (CA), and scanning electron microscope (SEM). The results indicate that the novel organic-inorganic hydrophobic nanocomposite with a core-shell structure was synthesized successfully. XRD analysis reveals the nanocomposite film has an amorphous structure, and FTIR analysis indicates the nanoparticles react with a silane coupling agent (methacryloxy propyl trimethoxyl silane KH570). Interestingly, the morphology of the nanoparticle film is influenced by the composition of the core. Further, comparing with the film synthesized by silica nanoparticles, the film formed from SiO2–Al2O3–TiO2 nanoparticles has higher hydrophobic performance, i.e., the contact angle is greater than 101.7°. In addition, the TEM analysis reveals that the crystal structure of the particles can be changed at high temperatures.

Preparation of epoxidized soybean oil-grafted Fe3O4–SiO2 as a water-dispersible hydrophobic nanocomposite for solid-phase extraction of rhodamine B

In this study, epoxidized soybean oil-grafted Fe3O4-SiO2 nanocomposite (Fe3O4-SiO2-ESBO) containing a hydrophobic surface and hydrophilic polar functional groups was synthesized. The sorbent showed excellent dispersibility in aqueous solution and was utilized for magnetic solid phase extraction of trace amounts of rhodamine B in aqueous solution prior to its determination using UV–Vis spectroscopy. The sorbent was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. The magnetite nanoparticles had spherical shape with their grain size of <20nm. The effects of pH, sorbent mass, uptake time on the sorption of rhodamine B on Fe3O4-SiO2-ESBO were investigated using Box–Behnken design. The adsorption capacity of the sorbent was 1355μg of rhodamine B per gram of sorbent. In optimal experimental conditions, the limit of detection, limit of quantification and enrichment factor of the proposed method were 3.94μgL−1, 13.13μgL−1 and 26, respectively. The proposed method was successfully applied to the separation and determination of rhodamine B in dish washing liquid, match tips and tap water samples with recoveries in the range 96.40–98.10%.

From forest residues to hydrophobic nanocomposites with high oxygen-barrier properties

A biorefinery of forest resources should be able to convert all components of trees, including the bark and other types of forest residues, into value-added products. Here, non-cellulosic polysacch ...

Fluorescent nanosensors via photoinduced polymerization of hydrophobic inorganic quantum dots for the sensitive and selective detection of nitroaromatics.

We developed an efficient one-pot strategy for the preparation of hydrophilic amine-functionalized nanocomposites by using hydrophobic fluorescence quantum dots ZnS:Mn(2+)@allyl mercaptan (QDs@AM) as building blocks through novel light-induced in situ polymerization. The average size of as-prepared hydrophilic nanocomposites was ∼50 nm, which could be further tuned by varying the concentrations of the monomers. Importantly, these nanocomposites were further utilized for the facile, highly sensitive, and selective detection of nitroaromatics. The linear ranges for 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) lie in 0.01-0.5 μg/mL and 0.05-8.0 μg/mL, respectively, barely interfered with by other nitroaromatics such as 2,4-dinitrotoluene (DNT) and nitrobenzene (NB). Moreover, the novel surface modification method developed here offered a general strategy for fabricating hydrophobic nanocomposites with hydrophilic properties and indicated various potential applications including sensing and imaging.

Formation of a nanohybrid composite between mesostructured cellular silica foam and microporous copper trimesate

A metal-organic framework HKUST-1 or Cu3(BTC)2 was synthesized in mesopores of a COOH functionalized mesostructured cellular silica foam (MCF(M)-COOH), resulting in a hydrophobic nanocomposite. The Cu3(BTC)2 formed in the MCF(M)-COOH has been prepared by a microwave method with sequential incorporation of copper nitrate and 1,3,5-benzenetricarboxylic acid in a water/ethanol mixture containing the MCF(M)-COOH. The nanocomposite was characterized by XRD, BET, FT-IR, TEM and solid state 13C NMR. The nanocomposite had a higher hydrophobic property than pure Cu3(BTC)2 and MCF(M)-COOH as a result of their hybridization. Moreover, the formation of the nanocomposite increased the sorption rate of cyclohexane vapor as compared with those of pure Cu3(BTC)2 and MCF(M)-COOH due to the increased hydrophobicity.

Development and characterization of poly ethyl metha acrylate–iron oxide(III) based hydrophobic liquid nanocomposite films

Select applications of hydrophobic nanocomposites include preparation of robust self-cleaning surfaces, water-repellent glass surfaces, and waterproofing textiles. Various nanocomposites have been reported in the literature; however, the relationship between the nanocomposite surface morphology and its hydrophobicity needs to be understood better. In the present work Fe 2O 3 nanoparticles and poly ethyl metha acrylate (PEMA) were used in varying proportions to obtain a series of model hydrophobic surfaces (spin-coated on glass substrate). The hydrophobicity of these surfaces was measured by static contact angle; a maximum of ∼103° was obtained at highest loading of iron oxide nanoparticles. These surfaces were also characterized using AFM. The contact angle and characterization data were used to test some of the models which have been proposed in the recent literature on prediction of contact angle for composite surfaces. It is proposed that the hydrophobicity of the iron oxide–PEMA surface is due to the physical roughness causing air entrapment as well as the chemical heterogeneity. Based on the experimental studies and the simulations using the recent models on contact angle, some general features of relationship between a composite surface morphology and its hydrophobicity is proposed.

Silica/Silicone Nanocomposite Films: A New Concept in Corrosion Protection

ABSTRACTThin films of silsesquioxane, (HSiO3/2)n, were applied to aluminum panels and to CMOS microelectronic circuit surfaces by spin or dip coating organic solutions of the silsesquioxane. Nanoporous silica was obtained by oxidation of the silsesquioxane. These nanoporous silica films were then vacuum infiltrated with various viscosities of polydimethylsiloxanes (PDMS) to form hydrophobic nanocomposites. The nanocomposite films were shown to provide superior hermetic protection against salt fog exposure when compared to PDMS and silica films alone.The composite films were characterized by FTIR and optical microscopy. FTIR spectra showed that the silica served as a skeletal framework holding the hydrophobic PDMS in place and preventing loss of adhesion. This is in contrast to PDMS films alone in which blistering of the film from the substrate can occur, thus, allowing ions and moisture to reach the surface and corrosion to take place.