xxiii πανελληνιο ÏƒÏ Î½ÎµÎ´ÏÎ¹Î¿ Ï†Ï ÏƒÎ¹ÎºÎ·Ï‚ στερεας καταστασης & επιστημης ...

Synthesis of Polymer Brushes onto Inorganic Nanoparticles
D. S. Achilleos, M. Vamvakaki
Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas,
711 10 Heraklion, Crete, Greece and
Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete, Greece
*achill@iesl.forth.gr; vamvakak@materials.uoc.gr
Nanoparticles have attracted much attention due to their fascinating electronic, optical, magnetic, and/or catalytic
properties associated with their nano- or quantum-scale dimensions. These include metal (Au, Pt, Pd, etc.), semiconductor
(CdS, CdSe, ZnS, etc.), and oxide (Fe 2 O 3 , Al 2 O 3 , TiO 2 , SiO 2 , etc.) nanoparticles [1]. The development of polymer/nanoparticle
composite materials is of greater interest due to the combination of both the properties of the inorganic nanoparticles and those
of the polymer (solubility, film formation, and chemical activity) [2]. Although the surface modification of silica particles by
the chemical attachment of polymer chains has been extensively reported [3], other particles, like CdS [4], Fe 2 O 3 [5] and TiO 2
[6] have been also used. However, so far there are no reports on the synthesis of chemically bound polymer/ZnO hybrids.
In the present work we describe the preparation of smart surface polymeric coatings onto inorganic nanoparticles.
The surface of TiO 2 (20 nm) and ZnO (~ 100 nm) nanoparticles has been modified with either hydrophilic or hydrophobic
polymer brushes synthesized by Atom Transfer Radical Polymerization (ATRP) utilizing the “grafting from” technique. The
hydrophilic monomers used for the polymer synthesis were oligo(ethylene glycol) methacrylate (OEGMA) (neutral, water
soluble, biocompatible) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) (ionizable, water soluble, cationic), while
methyl methacrylate (MMA) was employed as the hydrophobic monomer (see Figure 1).
O Br
HO OH
HO
OH
OH + Br
HO
HO
OH
2-bromoisobutyryl bromide
R
R
R
R
R
R
R
R
+
THF
N(Et) 3
Monomer
Solvent
R R
O
R
R R R=
R
R
R
+
Br
O
CH 3
CH 2 C
n
C O
O
CH 2
CH 2
O
10
H
CH 3
CH 2 C
CH 3
CH 2 C
C O
n
C O
CH 3
O
CH 2
O
CH 3
CH 2
N
Figure 1. Synthetic procedure followed for the synthesis of polymer brushes onto the inorganic nanoparticles
The organic/inorganic hybrids prepared were characterized by Thermogravimetric Analysis (TGA), Transmission
Electron Microscopy (TEM) and FTIR - Attenuated Total Reflectance (ATR) spectroscopy. Dispersion stability tests of the
polymer coated particles were performed to evaluate the efficiency of the polymeric stabilizer.
Results and Discussion
0,6
TiO 2 +OEGMA
Absorption
0,4
0,2
TiO 2 initial
0,0
4000 2000
Wavenumber(cm -1 )
Figure 2. FTIR – ATR spectra of the original and the POEGMA-coated TiO 2 nanoparticles
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