(180bl) Factorial Experiment Design in Colloid Nanoparticle Synthesis | AIChE

(180bl) Factorial Experiment Design in Colloid Nanoparticle Synthesis



FACTORIAL EXPERIMENT
DESIGN IN COLLOID NANOPARTICLE SYNTHESIS

Cun Wen,
University of South Carolina, Columbia, SC

Jason Hattrick-Simpers, University of
South Carolina, Columbia, SC

Jochen
Lauterbach, University of South Carolina, Columbia, SC

Recently, colloid nanoparticle synthesis has emerged as an effective way
to tune the morphology, structure, and size of nanoparticles. Colloid nanoparticle
synthesis involves multiple operation parameters, such temperature,
concentration, reduction agent, and gas environment. These parameters influence
the particle morphology and size in different manners and to varying degrees.
Together they form a multidimensional parameter space with non-linear
interdependencies between the parameter, such a space can be very time consuming
to map out and to interpret utilizing traditional experimental design and
synthesis protocols.

Herein, we demonstrate the application of factorial experimental design
to CoCu colloid core-shell nanoparticle synthesis. With
this approach a series of experiments that decouple the influences of 5
parameters in the synthesis procedure were studied. The 5 parameters include
reaction temperature, temperature ramping rate, and concentration of the
precursors, capping agent, and reductant. Though we
swept out a wide parameter space, the core-shell structures of the
nanoparticles are maintained. Among the five parameters, we found that the ramping
rate and the capping agent concentration are several orders of magnitude more effective
in controlling the particle size as compared to the other parameters. One representative
contour map based on factorial design is shown in figure 1. The effect of
ramping rates and capping agent concentration can be understood to increase the
nucleation speed, and thus lead to a reduction in the particle size.

Figure 1. The
contour map of the influence of temperature ramping rate and PVP concentration
on the particle size.

To summarize up, with the factorial design, the effects and
cross-effects of five synthesis parameters are quantitatively described. Furthermore,
following predictions from the factorial design, nanoparticles with small sizes
were successfully synthesized.