Haitao Lin

Lamellar phase formation in catanionic mixtures of hydrogenated and fluorinated surfactants: a comparative study

The properties and phase behaviors of the catanionic mixtures consisting of tetradecyltrimetylammonium bromide (TTABr) and different anionic surfactants (i.e., sodium docanoate, C10HOONa; sodium laurate, C12HOONa; sodium perfluorodecanoate, C10FOONa) were examined, in particular when the molar mixing ratio in the aqueous solution was exactly 1:1. Although the three inspected systems have identical head groups and counterions, they exhibited very different lamellar (Lα) phases. When using the hydrogenated surfactants, the C10HOONa–TTABr system formed domain-like Lα/L1 two phases and the C12HOONa–TTABr system formed cream-like Lα/L1 two phases, respectively. In the case of the perfluorinated surfactant, the C10FOONa–TTABr system formed interdigitated and tilted Lα gel. The microstructures of the three Lα phases were characterized by polarized microscope, freeze-fracture transmission electron microscope, small angle X-ray scattering, and X-ray diffraction. The phase transition of the lamellar gel at different temperature was studied by differential scanning calorimetry and rheological measurements. The results elucidated the formation of the Lα phase in catanionic mixtures containing hydrogenated or fluorinated anionic surfactants with molar mixing ratio of 1:1.

Effects of Byproduct Amendment on Enzyme Activities and Physicochemical Properties of Acidic Orchard Soil from Jiaodong Peninsula of China

ABSTRACT Application of byproduct amendment containing silicon, calcium, magnesium, and potassium has been shown to improve acidic soil quality in Jiaodong Peninsula of China. In this study, we explored the influences of amendment supplemented with and without urea on the physicochemical properties as well as microbial activities of acidic soil from Jiaodong over a 120-day period. With the amendment, the electronic conductivity and pH of soils changed. The amendment treatment significantly reduced inorganic nitrogen content and increased microbial biomass nitrogen content during the whole incubation period. The microbial biomass, activities of phenol oxidase and dehydrogenase were increased by the addition of amendments, while the soil respiration, catalase and urease activity were declined. Our results indicated that application of byproduct amendment could improve the chemical and biological properties of the acidic orchard soils from Jiaodong over a short time period of investigation.

The phase transition from L3 phase to vesicles and rheological properties of a nonionic surfactant mixture system

A sponge phase (L3 phase) was observed in aqueous solution of a nonionic surfactant polyethylene glycol ether of tridecyl alcohol with the average 3 of ethylene oxide (CH3(CH2)12(OCH2CH2)3OH, abbreviated as Trideceth-3) with tetradecyldimethylamino oxide (CH3CH213N↑OCH32

Humic acid slow release soil-modifying fertilizer and preparation method thereof

{\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{13}\overset{\overset{\mathrm{O}}{\uparrow }}{\mathrm{N}}{\left({\mathrm{CH}}_3\right)}_2

Integrated fertilization method under condition of NPKS of double-cropping crops of wheat and corn

, abbreviated as C14DMAO). The L3 phase can be transferred to planar lamellar phase after the bilayer was protonated by the formic acid formed through the hydrolysis of methylformate. The addition of surface charge into the nonionic L3 phase through electrostatic repulsion on the ionic head groups will suppress the Helfrich undulation and induce the transition to planar lamellar phase. The planar lamellar phase can be transformed into multilamellar vesicles under shear. Rheological properties show that both of the storage modulus and the loss modulus of the lamellar phase were increased with the increment of surface charge density. The phase transition from L3 phase to vesicles was characterized by rheological measurements, 2H NMR spectra, and transmission electron microscope (TEM) observations. To our best knowledge, this is the first example of a controlled phase transition in nonionic surfactant mixtures through protonation and shear forces. The procedure provides a direction on how to achieve phase transition in surfactant solution by changing the conditions and an application of phase transition of controlled materials.

Whole-nutrition biological flushing and spreading fertilizer and preparation method thereof

The transition from worm-like micelles to vesicles can take place in certain cationic–anionic (catanionic) systems such as the tetradecyltrimethylammonium laurate (TTAL) aqueous solution that is prepared by adding hydrochloric acid (HCl). It appears that the lamellar phase of 100 mmol · L−1 of TTAL aqueous solution should go through a series of phase transition processes under different pH conditions, in which the content of HCl is gradually increased. When the pH value was modulated to about 7, the lamellar phase became worm-like micelle phase. By further increasing the content of HCl, the worm-like micelle phase tends to separate into two phases. Specifically, the top phase seems to be turbid structure, whereas the lower phase is still worm-like micelle phase. In the worm-like micelle one phase (pH = 7.04), a phase transition from worm-like micelles to vesicles is evident with the increase in temperature. Therefore, such phase transition processes could be readily monitored by turbidity or rheological analyses. Dynamic light scattering and cryo-Transmission Electron Microscopy measurements were also employed to determine the structures before and after phase transition. Consequently, this work would yield new insights to understand the phase transition mechanism of catanionic surfactants induced by pH change. GRAPHICAL ABSTRACT