AOT微乳液中通过水化电子产额调控合成BaSO_4纳米纤维  

Synthesis of BaSO_4 Nanofibers Controlled by the Yield of Hydrated Electrons in AOT-Based Microemulsions

作　　者：徐文丽[1] 陈庆德[1] 沈兴海[1] 

机构地区：[1]北京大学化学与分子工程学院,放射化学与辐射化学重点学科实验室,北京分子科学国家实验室,北京100871

出　　处：《物理化学学报》2014年第6期1194-1200,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(91226112);高等学校博士学科点专项科研基金(20110001120121);国际原子能机构((CRPResearchContractNo.15107)资助项目~~

摘　　要：通过γ-辐照含有K2S2O8和BaCl2的二(2-乙基己基)琥珀酸酯磺酸钠(AOT)反相微乳液,将S2O82-通过辐射还原实现了SO42-的原位缓释,从而成功制备出BaSO4纳米纤维单晶,并进一步制得多层次的纳米纤维束结构.在此基础上,通过改变水与表面活性剂物质的量之比(ω值)、改变钡盐阴离子和在微乳液连续相添加芳香化合物等手段来调节水化电子(e-aq)产额,控制微乳液水池中S2O82-的还原和SO42-的缓释速率,成功实现了对BaSO4纳米粒子形貌的调控:随着ω值的增加或剂量率的增加,e-aq产额增加,从而加快了SO42-的释放,不利于BaSO4纳米纤维的生成;采用Ba(NO3)2为钡源时,NO3-能有效地降低e-aq产额和S2O82-的还原速率,因而在较高的剂量率和较高ω值下能得到BaSO4纳米纤维;在微乳液油相中加入甲苯来捕获油相中过量电子(e-oil),降低e-aq产额,从而在较高的剂量率下得到BaSO4纳米纤维.研究结果表明:通过e-aq产额调控纳米粒子形貌的机理在BaSO4纳米粒子的制备中得到很好体现.Single-crystal BaSO4 nanofibers and multi-architecture bundles were successful y synthesized in sodium bis（2-ethylhexyl） sulfosuccinate （AOT）-based microemulsions containing K2S2O8 and BaCl2, in which the control ed release of SO24-ions was realized in situ by the radiolytic reduction of S2O28-ions. The molar ratio of water to surfactant （ωvalues）, 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 （e-aq）. This al owed for control ing the reduction of S2O28- ions and the release of SO24- ions, leading to the shape manipulation of BaSO4 nanoparticle. With an increase inωvalues or dose rate, the yield of e-aq increased, which led to a quicker release of SO24-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 higherωvalue, because NO3-effectively decreased the yield of e-aq and the rate of S2O28-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 e-aq in the water pool decreased. This favored the formation of nanofibers at higher dose rates. These results showed that the mechanism about morphology＆amp;nbsp;control by the yield of e-aq was verified in the syntheses of BaSO4 nanoparticle.

关 键 词：BASO4 Γ-辐照 水化电子 反相微乳液 纳米纤维 

分 类 号：TQ343[化学工程—化纤工业] TQ132.35