Date of Award

Spring 2018

Project Type

Thesis

Program or Major

Chemical Engineering

Degree Name

Doctor of Philosophy

First Advisor

Nivedita Gupta

Second Advisor

Dale P Barkey

Third Advisor

Xiaowei Teng

Abstract

The attractive properties of nanoparticles and nanostructures has driven their integration into a wide range of modern technologies. Synthesis of nanoparticles in droplet flow reactors offers a solution to the shortcomings of batch reactors. The interphase droplet reactor presented in this work maintains the advantages of a droplet flow reactor while accomplishing reagent addition through mass transfer from the continuous phase to the droplet phase. In this work, sodium hydroxide in a continuous phase of 1-octanol diffuses into aqueous droplets containing a metal salt, initiating nanoparticle synthesis. An acid-base titration confirmed that increasing the total flow rate increased the rate of mass transfer. Addition of Triton X-100 surfactant increased the rate of mass transfer while sodium dodecyl sulfate did not. Zinc oxide nanoparticles with controllable sizes between 41 to 62 nm were produced by changing reaction temperature, reagent concentration, droplet volume, and adding surfactants. Operating the interphase droplet reactor at 25˚C produced large ZnO sheets and increasing the reaction temperature to 40˚C and above produced spherical nanoparticles. Higher inlet sodium hydroxide concentrations transitioned the particle morphology from spherical particles to plates. Decreasing the reactor diameter decreased the mean particle size from 54 nm to 43 nm. The interphase droplet reactor also produced a narrower particle size distribution than a single phase aqueous batch reactor. Low reagent concentrations produced ellipsoidal zinc oxide mesocrystals through oriented attachment. A reaction temperature of 40˚C was adequate for mesocrystal production. The presence of Triton X-100 did not prevent oriented attachment while the addition of sodium dodecyl sulfate did. The ability of the interphase droplet reactor to synthesize other metal oxides was demonstrated by the synthesis of copper (II) oxide. Copper oxide sheet mesocrystals were formed in the absence of acetic acid. The presence of acetic acid in the droplet phase inhibited oriented attachment and produced copper oxide nanowires.

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