Research On Microfluidic-Control Technology For Automated Controllable Preparation Of Precious Metal Nanoparticles

Nowadays,nanoparticles(NPs)have wide application.And the high-yield gold nanoparticles(Au NPs)or silver nanoparticles(Ag NPs)have good monodispersity,precise controllable-size.The preparation of these precious NPs has great development in many fields such as material synthesis,biological detection and optoelectronic device research.Researcher used the Au NPs as a main example.Nowadays,the research and application of the precious metal NPs are developing rapidly,and these NPs'preparation methods tend to be diversified.The demand for NPs in the research field and the nano-industry market is also increasing,although the traditional chemical preparation method has high reproducibility.The traditional Au NPs' preparation methods have some following limitations,including low production yield of per experiment,much complicated experimental process and so on.These past methods greatly restrict the development prospects and application effects about NPs,and gradually promote other modernization controllable high yield preparation methodsIn this work,based on the electromechanical automation system and the microfluidic chip and through the functional analysis of our device,I built a set of microfluidic controlling and preparation system with high degree of integration,functionalization,and easy and effective.The mixed reaction process of the phase method of step by step is introduced into the microfluidic control preparation system.The process can be divided into the following stages:solution input and delivery,parameter real-time regulation,in-chip mixing reaction,particle output and directional collection.Based on this controllable preparation mode,researcher prepared monodisperse Au NPs with the evenly distribution between 4.5 nm and 7 nm that had precise and controllable particle size.The relative error of particle size is less than 10%.Then we compared the experimental performance research and theoretical error analysis between two self-constructed devices.At the same time,the researcher carried out the concentration field simulation in microfluidic chip and analysis the influence of temperature stress error,and I also introduced process for micro-flow control preparation method of Ag NPs.It's a foundation for the research and development about the microfluidic control preparation method of this systematic work.This experimental study showed that these influencing factors have specific effects on the sizes of the nanoparticles(The sizes changed regularly with each influencing factors)including the reaction temperature(100?/70 ?),the total liquid phase flow rate in the chip(QA+QB:0.1/0.2/0.4 ml/min),the inter-liquid phase feed rate ratio(Au source solution/reducing agent solution:5:3/1:1),and the molar amount of the surfactant(0.2/1/2/10 mmol).And then,the researcher carried out continuously the device optimization by analyzing experimental error and theoretical simulation.The Au NPs were obtained based on the microfluidic control preparation mode.Their size and shape are not only accurate but also controllable.The preparation scale of our system is upgraded from the milligram production of the conventional chemical method to the gram level in the automatic mode,and even higher yield.It provides the nanotechnology's growing demand for NPs.The various applications of NPs will break through the original material consumption limit,and can achieve leapfrog development.In this work,based on the preparation mode about the continuous liquid-phase pump and the microfluidic chip,by controlling microscopic nucleation and growth process of the NPs by the mechanical controllable parameters in this system,the researcher achieved the controllable preparation of precious metal gold NPs with size and shape.And through the experimental control and theoretical analysis of the microfluidic devices with two different configurations,the researcher actually optimized the system.This work combined special device building mode with the microfluidic control preparation technology that could provide a new idea and process for the synthesis of traditional NPs.