Although the preparation and application of amphiphilic Janus nanosheets have been studied a lot, little is known about their colloidal properties to date, especially at the molecular level. In this work, we systematically investigated the microscopic interactions between amphiphilic Janus nanosheets with different surface chemistry and water molecules. It is shown that the introduction of functional groups has a significant influence on the occupied volume and available surface area of the Janus nanosheets in aqueous solution due to the two-dimensional nature. The hydrophobic functional groups force water molecules away from the surface of nanosheets by forming a steric barrier. In contrast, the deprotonated hydrophilic groups have a strong and directional binding to the surrounding water molecules to form structured water layers on the surface of nanosheets. The interaction energy between Janus nanosheets and water molecules is dominated by electrostatic interaction and exhibit a strong dependence on the degrees of alkyl modification, the length of alkyl chain, and the types of hydrophilic groups on the surface of Janus nanosheets. The order of the influence of hydrophilic groups on the interaction energy and hydrogen bonding between Janus nanosheets and water is COO– > SO4– > COOH > NH2 > OH at 300 K. Moreover, the temperature and cation concentration of the aqueous solution have a significant effect on the interaction between water and Janus nanosheets with deprotonated hydrophilic groups. These results not only improve the understanding of the colloidal behaviors of the amphiphilic Janus nanosheets in aqueous solution but also contribute to the development of novel Janus materials for engineering applications.
In order to study the aggregation of CO2 and organic liquid molecules in the binary systems of CO2+ organic liquid at near critical and supercritical condition of CO2, the radial distribution function of CO2-organic liquid molecules and organic liquid–organic liquid molecules in the liquid phase of the CO2+ organic liquid systems is calculated by molecular dynamic simulation in this work and compared with the results of our previous works. The results of the research show that the aggregates of CO2–CO2 molecules, CO2-organic liquid molecules and organic liquid–organic liquid molecules are coexisted in the liquid phase of CO2+ organic liquid system, respectively.
The relative molecular mass of lanolin is 778 by the method of VPO.At 45 ℃,the interfacial tension of lanolin kerosene solution with distilled water,w(Na_2CO_3)=1.2% and w(NaOH)=1.2% water solutions are respectively 5.25,0.21 and 0.20 mN/m.The emulsification performance of lanolin kerosene solution in distilled water and alkali water was measured at 30 ℃.The emulsion of lanolin in w(NaOH)=1.2% water solution is very stable. When the reaction time is 4 d,the mixed solution is emulsified completely,and the rate of water separation is zero.With increasing shear rate,the interfacial shear viscosity between w(lanolin)=0.1% kerosene solution and w(NaOH)=1.2% water solution decreases.
Terpolymeric microspheres were synthesized by the inverse suspension polymerization of functional monomers including AMPS, NVP, and AM. The morphology and size of the obtained microspheres were measured by scanning electron microscopy (SEM) and optical microscopy. Furthermore, the swelling performances of the obtained microspheres were measured with alaser particle analyzer (LPA), and the thermal stability of the microspheres obtained was measured by differential thermal analysis (DSC-TG) and high temperature experiments involving microsphere/water dispersion. The results revealed that the extreme value of the microsphere size distribution decreased from 280 μm to 20 μm as the stirring rate increased from 175 rpm to 500 rpm. At temperatures below 25°C, the maximum achieved swelling ratio of the microspheres was 21, and the thermal stability of the terpolymer microspheres was significantly higher than that of the dipolymer microspheres. The terpolymer/water dispersions were kept at 120°C for 19d before any damage was observed.
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