Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, School of Chemistry and Materials Science, Xi'an 710062, China.
J Colloid Interface Sci. 2009 Dec 1;340(1):119-25. doi: 10.1016/j.jcis.2009.08.011. Epub 2009 Aug 12.
In this work, we report the preparation of the Sm2O3 nanoparticle precursors (Sm(OH)3) via a simple W/O microemulsion process, in which microemulsions of cetyltrimethylammonium bromide (CTAB)/alkanol/1-octane/Sm(NO3)3 aqueous solution were added into sodium hydroxide (NaOH) aqueous solutions. The Sm2O3 nanoparticles were then prepared by calcining the precursors at 900 degrees C. Particularly, DeltaG(c-->i), which is the change in standard Gibbs free energy for transferring cosurfactant from the continuous phase to the microemulsion interface and can be used to estimate the thermodynamic properties of microemulsions, was determined using the dilution method. The effects of alkanol carbon chain length (1-pentanol, 1-hexanol, 1-heptanol and 1-octanol) and the reaction temperatures (298, 308, 318 and 328 K) on both DeltaG(c-->i) and Sm2O3 nanoparticle size have been investigated. Specifically, the Sm2O3 nanoparticle size, when calcined at 900 degrees C, was found to be mainly controlled by DeltaG(c-->i), and was thereby affected by the thermodynamic properties of microemulsions. The obtained products were characterized by DSC-TGA, XRD, TEM and UV-Vis. The results showed that DeltaG(c-->i) decreased with the increase in both the length of alkanol carbon chain and the reaction temperature, and the average size of Sm2O3 nanoparticles decreased as DeltaG(c-->i) decreased. The effect of microemulsion thermodynamic properties on Sm2O3 nanoparticle size reported here can provide some insights in controllable preparation of other rare earth oxide nanoparticles via the microemulsion route.
在这项工作中，我们通过简单的 W/O 微乳液法制备了 Sm2O3 纳米颗粒前体（Sm(OH)3），其中微乳液由十六烷基三甲基溴化铵（CTAB）/链烷醇/1-辛烷/Sm(NO3)3 水溶液组成，加入到氢氧化钠（NaOH）水溶液中。然后，通过将前体在 900°C 下煅烧来制备 Sm2O3 纳米颗粒。特别地，使用稀释法测定了从连续相转移到微乳液界面的助表面活性剂的标准吉布斯自由能变化（DeltaG(c-->i)），可用于估计微乳液的热力学性质。研究了链烷醇碳链长度（1-戊醇、1-己醇、1-庚醇和 1-辛醇）和反应温度（298、308、318 和 328 K）对 DeltaG(c-->i)和 Sm2O3 纳米颗粒尺寸的影响。具体而言，当在 900°C 下煅烧时，Sm2O3 纳米颗粒的尺寸主要由 DeltaG(c-->i)控制，因此受微乳液热力学性质的影响。通过 DSC-TGA、XRD、TEM 和 UV-Vis 对所得产物进行了表征。结果表明，DeltaG(c-->i)随着链烷醇碳链长度和反应温度的增加而降低，Sm2O3 纳米颗粒的平均尺寸随着 DeltaG(c-->i)的降低而减小。这里报道的微乳液热力学性质对 Sm2O3 纳米颗粒尺寸的影响可以为通过微乳液途径可控制备其他稀土氧化物纳米颗粒提供一些见解。
