Microfluidical Microwave Reactor for Synthesis of Gold Nanoparticles.

Olga Rac-Rumijowska,Helena Teterycz,Jan Macioszczyk,Piotr Słobodzian,Karol Malecha

doi:10.3390/mi8110318

Abstract

Microwave treatment can reduce the time of selected syntheses, for instance of gold nanoparticles (AuNPs), from several hours to a few minutes. We propose a microfluidic structure for enhancing the rate of chemical reactions using microwave energy. This reactor is designed to control microwave energy with much higher accuracy than in standard devices. Thanks to this, the influence of microwave irradiation on the rate of chemical reactions can be investigated. The reactor consists of a transmission line surrounded by ground metallization. In order to deliver microwave energy to the fluid under test efficiently, matching networks are used and optimized by means of numerical methods. The monolithic device is fabricated in the low temperature co-fired ceramics (LTCC) technology. This material exhibits excellent microwave performance and is resistant to many chemical substances as well as high temperatures. Fabrication of the devices is described in detail. Measurements of microwave parameters are performed and differences between simulation and experiment results are discussed. Finally, the usefulness of the proposed device is proved in exemplary synthesis.

Highlights

Microwaves are a time and space varying electromagnetic field
We propose a novel microwave microfluidic reactor that is based on low temperature co-fired ceramics (LTCC)
The performance of the proposed microwave reactor was assessed during the synthesis of gold nanoparticles (AuNPs)

Summary

Introduction

Microwaves are a time and space varying electromagnetic field. Their frequencies lay in the range that is typically defined from 300 MHz to 300 GHz. We propose a novel microwave microfluidic reactor that is based on LTCC. This technology was primarily developed to increase the capability of the thick-film technology, especially for applications in mainboards and high-frequency circuits [16]. The performance of the proposed microwave reactor was assessed during the synthesis of gold nanoparticles (AuNPs). DDeessiiggnn ooff tthhee MMiiccrroorreeaaccttoorr The proposed monolithic device for microwave treatment was fabricated in the LTCC technTohleogpyro(pDousPedonmt o9n51olsityhsitcemde,vDicuePfoonr tm, Wicriolmwianvgetotrne,aDtmEe, nUtSwAa)s. Conducting the gold ion reduction in the developed microwave reactor improved the rate of formation of gold nanoparticles about 20 times. FigurwFeiigt1uh3or.eut1Hm3.RiHcTrRoEwTMEaMviemitmraegaaegtmseseanantn.dd ssiizzee ddisistrtirbiubtuiotinosnosf ogfolgdonldanonpaanrotipclaerstiocbletasinoebdt:a(ian)ewdi:th(aa)ndw; i(tbh) and; (b) without microwave treatment

Findings

Discussion

Conclusions