Synthesis Of Gold Nanoparticles Using Pulsed Mixing Method With Piezoelectric Actuator

As a new type of fluid mixing way, pulsed micromixing method based on piezoelectricactuation is firstly studied at home. The research on this pulsed micromixing method not onlyhas important academic significance, but also has important application value in medical,biological, chemical and other fields.The pulsed mixing method based on piezoelectric actuation in this paper is newapplication of piezoelectric micropump. With making adjustment of driving voltage andfrequency of micropump, Tetrachloroauric acid(HAuCl4) and trisodium citrate(Na3C6H5O7)can achieve efficient turbulent mixing in a kind of Y-type micromixer. Then the synthesis ofAu nanoparticles is able to be controlled by the rate and quality of mixing.By comparing and analyzing to the output characteristics of one-chamber andtwo-chamber series piezoelectric micropump, two-chamber micropump possessing seriesconnection can achieve higher performance to easily control the output of pulsed fluid. Basedon design theory of piezoelectric micropump and the lamination technology, a high-functionaltwo-chamber series piezoelectric micropump is designed and manufactured. Then theexperiment research and test also have been done, and the test results indicate that thepressure of the two-chamber pump can obtain30kPa under50V voltage and200Hz frequencycondition. The flow rate of the two-chamber pump can obtain4.2ml/min under the samecondition.Based on the theory of micromixing and the needs of pulsed micromixing, a kind ofY-type micromixer is designed and taken Fluent simulation analysis. The simulation resultsindicate that the degree of mixing σ is approximately0.97under the flow channelcross-section dimensions of0.4mm×0.4mm, the inlet flow channel angle of60o, phasedifference of two pulsating fluid of180o, flow amplitude of4ml/min and the pulse frequencyof300Hz condition. The degree of mixing σ is approximately0.96under the flow channelcross-section dimensions of0.4mm×0.4mm, the inlet flow channel angle of60o, phasedifference of two pulsating fluid of180o, flow amplitude of3ml/min and the pulse frequencyof200Hz condition. According to the results of simulation above, a Y-type micromixer isdesigned and manufactured, which is suitable for pulsed micromixing method based onpiezoelectric actuation. Then the experiment research and test also have been done, and thetest results indicate that the pulsed mixing method based on piezoelectric actuation is aefficient micromixing way through the animation of mixing in Y-type micromixer recorded byCCD.In this paper, Au nanoparticles are produced using a pulsed mixing method with amicrofluidic device actuated by two-chamber series piezoelectric micropump. By adjustingdrving voltage, frequency and phase difference of driving signal, different morphology, particle size and dispersity of gold nanoparticles are synthesized. The experimental resultspresent that the mixing effect of phase difference of180o is much better than phasedifference of0o under50V voltage and200Hz frequency condition. Without PVP in reactionsolution, the nanoparticles agglomerate seriously. With PVP in reaction solution, the particlesize decreases and the nanoparticles have good monodispersity. By analyzing synthetic Aunanoparticles with different reagent concentration, Na3C6H5O7of0.5mM as a gold salt andHAuCl4of1.5mM as a reducing agent are mixed to obtain Au nanoparticles with highmonodispersity and good morphology.