金纳米流体的电场可调光学性质

利用多次还原法制备了不同粒径的金纳米颗粒，SEM和粒度分析表明其平均粒径分别为11 nm,35 nm和58 nm.进一步通过表面活性剂辅助的液相转移法制备出不同粒径的油基金纳米流体，测试了金纳米流体在电场作用下的光学性质.结果表明金纳米流体在电场作用下表现出明显的双折射现象，且随电场强度的变化双折射具有可调节性.金颗粒粒径和浓度对折射率有明显影响，在实验采用的浓度范围内，折射率随金颗粒浓度和粒径的增加而减小.最后，利用电流变液结构转变机理对金纳米流体的电致双折射进行了分析.关键词：纳米流体双折射电流变液

Tunable optical properties of Au nanofluids under electric field

Using a repeating deoxidization method, we prepared Au nanoparticles with different mean sizes of 11 nm, 35 nm and 58 nm. Then the Au nanoparticles were dispersed in mineral oil to form Au nanofluids by the surfactant-assisted phase transition technique. Under electric field, the optical properties of the Au nanofluids were measured. It was found that the Au nanofluids exhibit significant electric field-induced birefringence and the birefringence index can be adjusted by changing the external electric field strength. Furthermore, the birefringence index is influenced by the Au concentration and particle size. Within the suitable particle concentration range, the index decreases with the increase of Au concentration and particle size. Finally, we further discuss the electric field-induced birefringence phenomena of the Au nanofluids according to the structure transformation mechanism of electrorheological fluids under electric field.