Micellization in pH-sensitive amphiphilic block copolymers in aqueous media and the formation of metal nanoparticles.
Dynamic light scattering, potentiometric titration, transmission electron microscopy and atomic force microscopy have been used to investigate the micellar behaviour and metal-nanoparticle formation in poly(ethylene oxide)-block-poly(2-vinylpyridine), PEO-b-P2VP, poly(hexa(ethylene glycol) methacrylate)-block-poly(2-(diethylamino)ethyl methacrylate), PHEGMA-b-PDEAEMA, and PEO-b-PDEAEMA amphiphilic diblock copolymers in water. The hydrophobic block of these copolymers (P2VP or PDEAEMA) is pH-sensitive: at low pH it can be protonated and becomes partially or completely hydrophilic leading to molecular solubility whereas at higher pH micelles are formed. These micelles consist of a P2VP or PDEAEMA core and a PEO or PHEGMA corona, respectively, where the core forming amine units can incorporate metal compounds due to coordination. The metal compounds (e.g., H2PtCl6, K2PtCl6) can either be introduced in a micellar solution, where they are incorporated within the micelle core via coordination with functional groups, or can be added to a unimer solution at low pH, where they lead to a metal-induced micellization. In these micellar nanoreactors, metal nanoparticles nucleate and grow upon reduction with sizes in the range of a few nanometers as observed by TEM. The effect of the metal incorporation method on the characteristics of the micelles and of the synthesized nanoparticles is investigated.
Vamvakaki
Maria
M
Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion Crete, Greece.
Papoutsakis
Lampros
L
Katsamanis
Vasilios
V
Afchoudia
Theodora
T
Fragouli
Panagiota G
PG
Iatrou
Hermis
H
Hadjichristidis
Nikos
N
Armes
Steve P
SP
Sidorov
Stanislav
S
Zhirov
Denis
D
Zhirov
Vasilii
V
Kostylev
Maxim
M
Bronstein
Lyudmila M
LM
Anastasiadis
Spiros H
SH