Effect of fatty acids complexed with polyethyleneimine on the flow curves of TiO₂ nanoparticle/toluene suspensions

Abstract

a b s t r a c tA series of polyethyleneimine (PEI)-fatty acid complexes using oleic acid (OA), isostearic acid (ISA), and stearic acid (SA) were prepared through a simple process. While PEI was not soluble in toluene, the complex with OA and ISA became soluble when its additive content was greater than 5 mol% based on the ethyleneimine (EI) unit of PEI. PEI-SA had similar solubility in toluene when more than 5 mol% of SA was added; however, the complex precipitated when the additive ratio of SA was increased to 40 mol%. The effect of fatty acid of PEI complexes on their TiO 2 nanoparticle adsorption properties and the flow curves of TiO 2 nanoparticle/toluene suspension was then studied using PEI complexed with 30 mol% of fatty acids. Surprisingly, while PEI-OA and PEI-ISA complexes effectively adsorbed on TiO 2 nanoparticles until saturation, the amount of adsorbed PEI-SA increased continuously. Comparing the flow curves of TiO 2 /toluene suspensions under 1.4 mg/m 2 addition of PEI-fatty acid complexes, where PEI-OA and PEI-ISA were under saturated adsorption, it was confirmed that PEI-OA effectively stabilizes TiO 2 nanoparticles in toluene without imparting thixotropic properties up to 30 vol%, while the suspensions with PEI-SA and PEI-ISA were solidified at lower volume contents and had high thixotropic properties.

Silver nanoparticles from insect wing extract: Biosynthesis and evaluation for antioxidant and antimicrobial potential

“…These fatty acids are situated within wings membrane under the epicuticular surface [ 13 , 44 ]. The components present in Mang Mao wings extract corresponds with that of previous reports on nanoparticles synthesis [ 39 , 45 , 46 ].…”

Rapid three-dimensional structuring of transparent SiO2 glass using interparticle photo-cross-linkable suspensions

“…Preparation of photo-responsive suspension. First, PEI-OA complexes with different OA contents (15-50 mol% of OA in PEI monomer units, calculated assuming all amines were secondary amines) in PEI were prepared in a manner similar to that in our previous report [34][35][36][37] . Briefly, 0.500 g of PEI and 0.493, 0.986, and 1.642 g of OA, corresponding to 15, 30, and 50 mol% OA, respectively, were mixed with α-terpineol to prepare a 10.0 g solution.…”

“…Briefly, 0.500 g of PEI and 0.493, 0.986, and 1.642 g of OA, corresponding to 15, 30, and 50 mol% OA, respectively, were mixed with α-terpineol to prepare a 10.0 g solution. The obtained solutions were treated in an ultrasonic bath for 5 min, and then magnetically stirred for 24 h. The respective PEI-OA were then dissolved into various mixed solutions of α-terpineol and THF (THF contents: 0, 30,35,40,45,50,55,60, and 100 vol%). SiO 2 fine particles (42 vol%) and ZrO 2 balls (φ 5 mm, volume fraction of the suspension: balls = 100:32) were added into the as-prepared solution.…”

“…Briefly, SiO 2 fine particles are dispersed in a mixed solvent of α-terpineol and tetrahydrofuran (THF) with assistance from polyethyleneimine partially complexed with oleic acid (PEI-OA). PEI-OA is designed to serve as a universal functional polymer dispersant that could be attached onto various series of particles [34][35][36][37] . The content of OA segment in PEI-OA is varied to tune the dispersion stability of SiO 2 fine particles in the solvent while the remaining un-complexed amino groups in PEI-OA were expected to act as cross-linking reaction sites.…”

Insect wing extract: A novel source for green synthesis of nanoparticles of antioxidant and antimicrobial potential

“…The stability of MMAgNPs was monitored up to 120 days (weekly once) and there was no change in absorbance at 430 nm (data not shown). This indicated strong stability of biosynthesized MMAgNPs which might be attributed to presence of carboxylate group in proteins that may result in stable nanoparticles [20].…”