cm5b02020_si_001.pdf (573 kB)
Monodipserse Nanostructured Spheres of Block Copolymers and Nanoparticles via Cross-Flow Membrane Emulsification
journal contribution
posted on 2015-09-22, 00:00 authored by Jae Man Shin, Minsoo P. Kim, Hyunseung Yang, Kang Hee Ku, Se Gyu Jang, Kyung
Ho Youm, Gi-Ra Yi, Bumjoon J. KimMonodisperse colloidal particles
of polystyrene-b-polybutadiene (PS-b-PB) block copolymers (BCPs)
were successfully prepared, in which uniform emulsions containing
BCPs were first generated by cross-flow membrane emulsification using
tubular Shirasu porous glass (SPG) membrane, and then unique internal
nanostructures were developed by controlled evaporation of solvent
inside emulsion. The diameter of those BCP particles could be controlled
from 200 nm to 5 μm by tuning the pore diameter of the membrane.
With symmetric BCPs, onion-like nanostructures inside particles were
formed. Coiled cylinders in the BCP particles were also developed
by adding homopolymers, in which the assembled BCP structure is strongly
dependent on the particle size, demonstrating the importance of our
membrane method in generating monodisperse BCP particles. Further
investigation of process parameters showed that for a given pore diameter,
the operation pressure (P) and surfactant concentration
were critical parameters for narrow size distribution of the particles.
Uniform emulsions were produced when the ratio of the operation pressure
to the critical pressure (P/Pc) was less than 4.33. In addition, uniformly
sized, hierarchically structured particles of BCPs and nanoparticles
(NPs) were produced, in which oleylamine-coated, 3 nm sized Au NPs
were incorporated selectively into the PB domains inside the particles.