Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (6): 1194-1200.doi: 10.3866/PKU.WHXB201404291

• PHOTOCHEMISTRY AND RADIATION CHEMISTRY • Previous Articles    

Synthesis of BaSO4 Nanofibers Controlled by the Yield of Hydrated Electrons in AOT-Based Microemulsions

XU Wen-Li, CHEN Qing-De, SHEN Xing-Hai   

  1. Beijing National Laboratory for Molecular Sciences, Fundamental Science on Radiochemistry and Radiation Chemistry Laboratory, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2014-03-28 Revised:2014-04-28 Published:2014-05-26
  • Contact: CHEN Qing-De, SHEN Xing-Hai E-mail:qdchen@pku.edu.cn;xshen@pku.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (91226112), Specialized Research Fund for the Doctoral Program of Higher Education of China (20110001120121), and Coordinated Research Projects of International Atomic Energy Agency (CRP Research Contract No. 15107).

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Abstract:

Single-crystal BaSO4 nanofibers and multi-architecture bundles were successfully synthesized in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)-based microemulsions containing K2S2O8 and BaCl2, in which the controlled release of SO42-ions was realized in situ by the radiolytic reduction of S2O82-ions. The molar ratio of water to surfactant (ω values), the counterions of Ba2+, and the addition of aromatic compounds into the oil phase of the microemulsions were used to adjust the yield of hydrated electrons (eaq-). This allowed for controlling the reduction of S2O82- ions and the release of SO42- ions, leading to the shape manipulation of BaSO4 nanoparticle. With an increase in ω values or dose rate, the yield of eaq- increased, which led to a quicker release of SO42- ions, and this did not favor the formation of BaSO4 nanofibers. When BaCl2 was replaced with Ba(NO3)2 the formation of nanofilaments became possible at a higher dose rate and a higher ω value, because NO3-effectively decreased the yield of eaq- and the rate of S2O82- ion reduction. When toluene was added into the oil phase of the microemulsions, the excess electrons were effectively scavenged in the oil phase, and the concentration of eaq- in the water pool decreased. This favored the formation of nanofibers at higher dose rates. These results showed that the mechanism about morphology control by the yield of eaq- was verified in the syntheses of BaSO4 nanoparticle.

Key words: BaSO4, γ-Irradiation, Hydrated electron, Reverse microemulsion, Nanofiber