Surfactant octadecylamine

In 1997, a Chinese research group [78] used the colloidal solution of 70-nm-sized carboxylated latex particles as a subphase and spread mixtures of cationic and other surfactants at the air-solution interface. If the pH was sufficiently low (1.5-3.0), the electrostatic interaction between the polar headgroups of the monolayer and the surface groups of the latex particles was strong enough to attract the latex to the surface. A fairly densely packed array of particles could be obtained if a 2 1 mixture of octadecylamine and stearic acid was spread at the interface. The particle films could be transferred onto solid substrates using the LB technique. The structure was studied using transmission electron microscopy. 

Hidalgo et al. [509] reported a method for the determination of molybdenum (VI) in natural waters based on differential pulse polarography. The catalytic wave caused by molybdenum (VI) in nitrate medium following preconcentration by coflotation on ferric hydroxide was measured. For seawater samples, hexadecyltrimethylammomum bromide with octadecylamine was used as the surfactant. The method was applied to molybdenum in the range 0.7-5.7 Xg/l. 

As a cationic polymer and a cationic amphiphile, poly(allyl amine hydrochloride) (PAA) and octadecylamine (ODA) shown in Fig. 6 were used, respectively. The stability of the monolayers of the anionic amphiphiles was increased by polyion-complexation with PAA added in the aqueous subphase in comparison with Ca2+ salt formation. Ion complexation (1 1) of each anionic amphiphile with ODA was also performed at the air-water interface by spreading a chloroform solution of a 1 1 surfactant mixture. 

Common separation methods can be divided into chemical and physical routes. Chemical approaches rely on the interaction of the surface of different CNT types with surfactant molecules. Early work has shown that octadecylamine [94] and agarose gel [95] adsorb preferably on semiconducting SWCNTs, while diazonium reagents [96] and DNA [97, 98] show preference with metallic tubes. The assemblies with adsorbed molecular species are considerably larger and heavier than the indi-... 

Transmission electron microscopy (TEM) has been an underutilized yet valuable too in particle size characterization of MC particles in LB films. Monolayer films of trioctylphosphine oxide-capped CdSe (18), spread as a monolayer on an aqueous subphase, were transferred to a TEM grid. A close-packed hexagonal arrangement of 5.3-nm (cr —4%) crystallites was found. TEM images were also obtained for HMP-stabilized CdS incorporated in BeH/octadecylamine films (79) and for CdS formed under an amine-based surfactant monolayer and transferred to a TEM grid (14). In one study, direct viewing of CdS and CdSe particles made from Cd2+-FA films on TEM grids was not possible due to poor phase contrast between the particles and the film (30). Diffraction patterns were observed, however, that were consistent with crystalline (3-CdS or CdSe. Approximately spherical particles of CdSe could... 

Zhou et al. reported the synthesis of flower-like ceria NPs by thermal decomposition of (NH4)2Ce(N03)g in OA/OM solvents at 230-300 °C. The small ceria nanoparticles form, assemble, and fuse mainly via (111) faces by oriented attachment. Monitoring by in situ electrical resistance measurements shows that the conductive species are diminished when the flower-like nanostructures form (Zhou et al., 2008a Figure 6). Ceria nanoflowers and nanocubes are also obtained in octadecylamine, with higher temperature for nanoflower and lower temperature for nanocubes. The obtained colloidal nanoparticles can be self-assembled into nanospheres assisted by SDS surfactants (Wang et al., 2008a). 

CPC exhibited the highest As removal efficiency (96%) when used in combination with RC membranes of 3 and 10kDa(YM3 andYMlO, Amicon, USA). The removal of arsenate with hex-adecyltrimethylammonium bromide (CTAB), benzalkonium chloride (BC) and octadecylamine acetate (ODA) at a surfactant concentration of 10 mM was of 94, 81 and 55%, respectively (Iqbal etal, 2007). 

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