Surface Properties of Silane-Treated Diatomaceous Earth Coatings: Effect of Alkyl Chain Length

Abstract

Modification of diatomaceous earth (DE) was performed using alkyltrimethoxysilanes of different chain lengths (C3, C8, C12, C16, and C18), and their resultant properties were determined. The thermal properties of these alkyltrimethoxysilane-treated DE powders were probed using thermogravimetric analysis and temperature-modulated differential scanning calorimetry, and the surface/porosity was studied using nitrogen adsorption and electron microscopy. Crystallinity of the hydrocarbon tails occurred when the chain lengths were C12 or larger, and the adsorbed hydrocarbon amounts were 1.6 mg/m or more. The wettability of functionalized DE-containing surfaces was studied using water contact angle measurements. At larger adsorbed amounts of 2.2 mg/m or more, the treated DE formed superhydrophobic coatings (with water contact angles ≥150°) with a polyurethane binder. These coatings required a minimum of 30% particle loadings, which allowed the DE particles to dominate the surface. At loadings larger than approximately 50%, there was a decrease in the contact angles corresponding to a reduction in roughness on the surface. Samples with adsorbed amounts less than 2.2 mg/m or chain lengths shorter than C12 were only hydrophobic. These results were in agreement with scanning electron microscopy and Brunauer-Emmett-Teller specific surface area and pore volume measurements.

Superswelling Hybrid Sponge from Water Glass for Selective Absorption of Crude Oil and Organic Solvents

“…With an increase in the alkyl chain length, the water contact angle will be improved, and also, aligned long alkyl chains ( n ≥ 12) can repel the water from the surface because of their low surface energies. 42 Due to the short alkyl chain length of TMES and VTMS, their contact angle is lower in comparison with the sample IOHSO, which is functionalized with OTMS. For IOHSV, an ordered range of surface coverage was not achieved, which is reflected in the lower contact angle value of 108 ± 1°.…”

Therapeutic Applications of Phytoplankton, with an Emphasis on Diatoms and Coccolithophores

“…In vitro --In vitro Antithrombogenic and antimicrobial biomaterials [65] Diatomite -(PS, PVAc), [68] epoxy and polyurethane binders, [70] alkyltrimethoxysilane, [71] (PPFS, PSMA, PDMSMA), [72] fluorosilanes [69,73] In vitro --In vitro Superhydrophobic surfaces [68][69][70][71][72][73] Diatomite -Amino groups (APTES) reacted with TRITC In vitro H1355 human epidermoid cancer cells -In vitro Drug delivery, cancer treatment [50] Diatomite -Amino groups (APTES) followed by PEGylation f) and bioconjugation with CPP, Alexa Fluor 488 dye…”

“…[70] The superhydrophobicity of diatomaceous earth particles was also studied using grafted alkyltrimethoxysilane [CH 3 (CH 2 ) n-1 (OCH 3 ) 3 ], with an increasing chain length (n = 3, 8, 12, 16, and 18). [71] The morphology of diatomaceous earth, amount of grafted alkyltrimethoxysilane, and chain length played an important role in the formation of superhydrophobic materials. Modification of the diatomaceous earth particles with poly(pentafluorostyrene) (PPFS), poly(stearyl methacrylate) (PSMA), and poly(dimethyl siloxane methacrylate) (PDMSMA) was also attempted to render superhydrophobicity of the particles.…”

“…Therefore, the minimum loading amount of diatomaceous earth treated with HFIP‐TMS inducing superhydrophobicity in polymer coatings might vary, as different amounts of fluorosilanes covers the pores and hence decreases the surface area of the particles . The superhydrophobicity of diatomaceous earth particles was also studied using grafted alkyltrimethoxysilane [CH 3 (CH 2 ) n ‐1 (OCH 3 ) 3 ], with an increasing chain length ( n = 3, 8, 12, 16, and 18) . The morphology of diatomaceous earth, amount of grafted alkyltrimethoxysilane, and chain length played an important role in the formation of superhydrophobic materials.…”

Enhancement of hydrophobicity of natural rubber latex films using diatomaceous earth

“…Their exoskeletons contain mainly amorphous silicon dioxide (SiO 2 ) (86%-94%), and smaller amounts of alumina (Al 2 O 3 ) and ferric oxide (Fe 2 O 3 ). 4 DE particles are about 1-500 μm in their largest dimension. 5 DE has a lightweight, highly porous structure with nano-scale surface roughness.…”