Controllable adsorption and ideal H-aggregation behaviors of phenothiazine dyes on the tungsten oxide nanocolloid surface.
Controllable adsorption and ideal H-aggregation behaviors of phenothiazine dyes on the tungsten oxide nanocolloid surface.
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DOI：
10.1021/la902174s
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发表时间：
2010-01
期刊：
影响因子：
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通讯作者：
Kenta Adachi;Tomohiro Mita;T. Yamate;S. Yamazaki;Hideaki Takechi;H. Watarai
中科院分区：
文献类型：
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作者：
Kenta Adachi;Tomohiro Mita;T. Yamate;S. Yamazaki;Hideaki Takechi;H. Watarai
采用紫外可见光谱法研究了四种吩噻嗪（PN）染料（噻吩（TH）、亚甲基蓝（MB）、新亚甲基蓝（NMB）和1，9-二甲基亚甲基蓝（DMB））在氧化钨（WO（3））纳米胶体溶液中的单体-聚集体平衡。在WO（3）纳米胶体溶液中加入PN染料后，其吸收光谱发生了明显的变化，表明在WO（3）纳米胶体表面形成了H型（面对面）三聚体。PN染料在WO（3）纳米胶体表面的吸附能力随着离子强度的增加而减弱，表明阳离子PN染料与带负电荷的WO（3）纳米胶体之间存在静电相互作用。通过对各光谱数据的详细分析，深入研究了PN染料分子结构对WO（3）纳米胶体表面吸附和聚集行为的影响。此外，使用离心液膜（CLM）技术原位测量PN染料聚集显示PN染料在WO（3）纳米胶体表面的聚集以两步三阶段（单体-->二聚体-->三聚体）形成进行。根据Kasha的激子理论，讨论了PN染料在WO（3）纳米胶体表面的聚集机理。
The monomer-aggregate equilibrium of four phenothiazine (PN) dyes, containing thionine (TH), methylene blue (MB), new methylene blue (NMB), and 1,9-dimethylmethylene blue (DMB), in the tungsten(VI) oxide (WO(3)) nanocolloid solution has been investigated by means of UV-vis spectroscopy. Addition of PN dye into the WO(3) nanocolloid solution brought about significant changes in the absorption spectrum, suggesting the formation of H-type (face-to-face fashion) trimer on the WO(3) nanocolloid surface. The adsorptivity of PN dyes onto the WO(3) nanocolloid surface was diminished by the raising the ionic strength, indicating the evidence of the electrostatic interaction between cationic PN dye and negatively charged WO(3) nanocolloids. The detail analysis of each spectral data provided insight into the effect of molecular structure of PN dyes on the adsorption and aggregation behaviors on the WO(3) nanocolloid surface. Moreover, in situ measurement of PN dye aggregation using the centrifugal liquid membrane (CLM) technique revealed that the aggregation of PN dyes on the WO(3) nanocolloid surface proceeded in a two-step three-stage (monomer --> dimer --> trimer) formation. The aggregation mechanism of PN dyes on the WO(3) nanocolloid surface was discussed on the basis of Kasha's exciton theory.