title: Micellization in pH-sensitive amphiphilic block copolymers in aqueous media and the formation of metal nanoparticles.
abstract: 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.
authors.affiliation: Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion Crete, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Vamvakaki
authors.forename: Lampros
authors.initials: L
authors.lastname: Papoutsakis
authors.forename: Vasilios
authors.initials: V
authors.lastname: Katsamanis
authors.forename: Theodora
authors.initials: T
authors.lastname: Afchoudia
authors.forename: Panagiota G
authors.initials: PG
authors.lastname: Fragouli
authors.forename: Hermis
authors.initials: H
authors.lastname: Iatrou
authors.forename: Nikos
authors.initials: N
authors.lastname: Hadjichristidis
authors.forename: Steve P
authors.initials: SP
authors.lastname: Armes
authors.forename: Stanislav
authors.initials: S
authors.lastname: Sidorov
authors.forename: Denis
authors.initials: D
authors.lastname: Zhirov
authors.forename: Vasilii
authors.initials: V
authors.lastname: Zhirov
authors.forename: Maxim
authors.initials: M
authors.lastname: Kostylev
authors.forename: Lyudmila M
authors.initials: LM
authors.lastname: Bronstein
authors.forename: Spiros H
authors.initials: SH
authors.lastname: Anastasiadis