Viriya-Empikul N, Sano N, Charinpanitkul T, Kikuchi T, Tanthapanichakoon W
Center of Excellence in Particle Technology, Department of Chemical Engineering, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand. Department of Mechanical and System Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2201, Japan.
Nanotechnology. 2008 Jan 23;19(3):035601. doi: 10.1088/0957-4484/19/03/035601. Epub 2007 Dec 11.
It was experimentally confirmed that the average length of titanate nanotubes (TNTs) can be increased and controlled to a certain degree by applying sonication pretreatment to their titania precursors prior to hydrothermal synthesis. Without sonication, the average length of the TNTs synthesized by the hydrothermal process was much shorter due to constricted diffusion of the hydroxyl ion (OH(-)) and the sodium ion (Na(+)) through the narrow interparticle space of agglomerated titania precursors, thereby retarding the TNT formation mechanism. On the other hand, much longer TNTs with an average hydrodynamic size of 490-1760 nm were produced when the sonication pretreatment was applied. Based on microscopic observations on the transformation of the present precursors and the reported nanotube formation phenomena during the hydrothermal process, a mechanism contributing to length control is proposed.
实验证实，通过在水热合成之前对二氧化钛前驱体进行超声预处理，钛酸纳米管（TNTs）的平均长度可以在一定程度上增加并得到控制。在没有超声处理的情况下，由于羟基离子（OH(-)）和钠离子（Na(+)）通过团聚的二氧化钛前驱体的狭窄颗粒间空间扩散受限，水热法合成的TNTs平均长度要短得多，从而阻碍了TNT的形成机制。另一方面，当进行超声预处理时，会产生平均流体动力学尺寸为490 - 1760 nm的长得多的TNTs。基于对当前前驱体转变的微观观察以及水热过程中报道的纳米管形成现象，提出了一种有助于长度控制的机制。
