Self-Assembly of Maltoheptaose-<i>block</i>-Polystyrene into Micellar Nanoparticles and Encapsulation of Gold
Nanoparticles
- Publication date
- Publisher
Abstract
The present paper discusses the controlled
self-assembly of sugar-containing
block copolymer, maltoheptaose-<i>block</i>-polystyrene
(MH<sub>1.2k</sub>-<i>b</i>-PS<sub>4.5k</sub>), into micellar
nanoparticles of ca. 30 nm radius in aqueous media and their possibility
of gold encapsulation. Micellar association of MH<sub>1.2k</sub>-<i>b</i>-PS<sub>4.5k</sub> into nanoparticles was demonstrated
by mixing a large amount of water (MH-selective solvent) with a solution
of MH<sub>1.2k</sub>-<i>b</i>-PS<sub>4.5k</sub> in a mixture
of tetrahydrofuran (THF) (PS-selective solvent) and water with a certain
weight fraction [4:1 (w/w) THF/water], where MH<sub>1.2k</sub>-<i>b</i>-PS<sub>4.5k</sub> exists as well-swollen single chains,
followed by evaporation of THF. The mean hydrodynamic radii (<i>R</i><sub>h</sub>) of the nanoparticles were determined by dynamic
light scattering (DLS) to be ca. 30 and 80 nm depending upon the method
of preparation. The resulting nanoparticles were clearly visualized
by transmission electron microscopy (TEM), atomic force microscopy
(AFM), and field emission gun–scanning electron microscopy
(FEG−SEM) imaging and complemented by nanoparticle tracking
analysis (NTA) using a NanoSight instrument. The preliminary study
of the self-assembly of MH<sub>1.2k</sub>-<i>b</i>-PS<sub>4.5k</sub> in the presence of gold nanoparticles functionalized with
PS chains grafted on their surface indicated potential possibilities
of encapsulation of gold nanoparticles into the block copolymer nanoparticles
in aqueous media