Fluorinated Surfactants and Fluorinated Polymer Materials(Ⅰ): General Review

Fluorinated surfactants and fluorinated functional materials were introduced. Their fundamental concept, classification and structure, major physicochemical properties, industrial production methods, as well as applications in industrial and high technological fields were summarized. Their current environmental problems and the countermeasures in this field were also briefed.

Fluorinated Surfactants and Fluorinated Polymer Materials(Ⅱ):Environmental and Safety Issues

The environmental and safety issues of perfluorooctane sulfonyl fluoride/perfluorooctane sulfonic acid/ perfluorooctane sulfonates (PFOS) were introduced in detail by summarizing several published reviews, including their production, occurrence and emission in environment, exposure and intake to human being, supervision and emission reduction, long-distance transport, bioaccumulation and excretion, degradation and toxicity. Opinion with respect to safety issues of PFOS was also proposed in view of surfactant working field in order to upgrade their application value. The overreaction in the current state for the fear of “fluorine” was concerned. For fire-fighting foams, the issue of “safety” needs to be critically weighed.

Fluorinated Surfactants and Fluorinated Polymer Materials(Ⅳ): Strategy for Solving PFOS Problems

Fluorinated alkyl substances are irreplaceable in many fields because of the special properties of fluorocarbon chains.Many efforts have been made to solve the historic problems of PFOS.In this paper,several strategies were discussed,including the possibilities in the methods of degradation,separation,recycling use,and reducing the using concentration.The most reliable one is to obtain replacement products of PFOS.Several kinds of replacement products were introduced and their feasibility of application was also discussed.

Fluorinated Surfactants and Fluorinated Polymer Materials(Ⅲ): Personal Opinion on the Problems of PFOS

As surfactant researchers, we have discussed the current problems of PFOS in China from our personal standpoint. The difficulties in both elimination and investigation on PFOS are analyzed. The production, application, biodegradation and regulation for some other important fluorinated alkylated substances are also briefly introduced. Finally, the objective and tasks for surfactant researchers are pointed out.

Effects of Hydroxyl Groups in Organic Ammonium Counterions on the Properties of Fluorinated Surfactants

The surface tension, foaming and viscosity for C_7F_(15)COO^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x) and C_8F_(17)SO_3^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x)(x=0, 1,2, 3) were measured to systematically study the effects of hydroxyl groups in organic ammonium counterions on the properties of perfluorooctanoates and perfluorooctanesulfonates. The results showed that the critical micelle concentration (cmc) and the surface tension at cmc (γ_(cmc)) were both increased with the increase of number of hydroxyl groups (x) in the two series. The perfluorooctanesulfonate had smaller cmc but higherγ_(cmc) than perfluorooctanoate with the same counterion. The minimum molecular area of surface adsorption (A_(min)) of C_8F_(17)SO_3^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x) were 0.64, 0.57, 0.63 and 0.72 nm^2 while the A_(min) values of C_7F_(15)COO^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x) were 0.61, 0.62, 0.61 and 0.71 nm_2 when x=0, 1, 2 and 3,respectively. For the investigated systems of surfactants, the results of foam expansion ratio agreed with those of surface activity, while the 25% drainage time were consistent with the results of viscosity.

Dielectric Spectra of Aerosol OT/Water Systems at Different Concentrations and Temperatures

The dielectric spectra of aerosol OT[AOT, sodium（bis-2-ethylhexyl）sulfosuccinate]/water systems at different concentrations and temperatures were investigated by the dielectric relaxation spectroscopy（DRS）. Through the dielectric spectra of different concentrations, two dielectric relaxations were observed over a frequency range from 40 Hz to 110 MHz and the mechanisms of the relaxations were also interpreted based on the Grosse’s model. The low-frequency relaxation（around 105 Hz） was attributed to the radial diffusion of counterions along the long-half axis of the rod-like micelle, and the high-frequency relaxation（around 106 Hz） was ascribed to the radial diffusion of counterions along the short-half axis. Furthermore, specific emphasis was placed on studying the effects of temperature on system’s conductivity. It was observed that the low-frequency limit of conductivity（κl） decreased and then increased with the increment of temperature under the measured concentration. On the other hand, the conductivity（κm and κh） in meso- and high-frequency ranges always increased as temperature increased. Both the tendencies of alteration which mentioned above should be related to the phase transition of AOT/water system.