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Glass Doping through Sol-Gel Chemistry :
a little something
can make a big difference
Jean-Marie Nedelec
Laboratoire des Matériaux Inorganiques, CNRS UMR 6002 ,
Université Blaise Pascal, Clermont-Ferrand 2
& Ecole Nationale Supérieure de Chimie de Clermont-Ferrand
FRANCE
Society of Glass Technology Annual meeting, (10-12 September, Cambridge, UK)

PARIS
CLERMONT-FERRAND
MONTPELLIER

Port Doctoral position
opening – 1 year
J-marie.nedelec@univ-bpclermont.fr

Outline
Introduction
Silica xerogels : Effect of doping on the densification
pathway
Bioceramics : Improved bioactivity of doped ceramics
Conclusions

Introduction
Doping = atoms, ions, molecules,…
= FUNCTION
Optical, magnetic, biological,
electrical,…
= STRUCTURE
Phase, hardness,
microstructure

Introduction
Sol-Gel Chemistry
Nanoparticles
Gel
Powder
Doping
Thin films
Very versatile route, high homogeneity,
good dispersion of doping ions

Doped Silica xerogels
Doping with rare earth ions, TM ions, dyes, biomolecules,…
No effect of doping on the structure of the gels

2,2
2,0
1,8
SiO 2
SiO 2
: Ag +
SiO 2
: Ce 3+
Density (g/cm 3 )
1,6
1,4
1,2
1,0
0,8
0,6
800 850 900 950 1000 1050 1100 1150
Annealing Temperature (°C)

D 1
δ Si-O-Si
D 2
ν Si-OH
1100°C
Intensity (a.u.)
1050°C
1000°C
950°C
900°C
850°C
800°C
0 200 400 600 800 1000 1200
Raman shift (cm -1 )

Normalized Raman Intensity
0,060
0,055
0,050
0,045
0,040
0,035
0,030
0,025
750 800 850 900 950 1000 1050 1100 1150 1200
0,04
0,03
0,02
D1
Si-OH
0,12
0,10
0,08
0,06
0,04
0,02
0,00
750 800 850 900 950 1000 1050 1100 1150 1200
0,84
0,80
0,76
0,72
Si-O-Si
D2
0,01
0,68
0,00
750 800 850 900 950 1000 1050 1100 1150 1200
0,64
750 800 850 900 950 1000 1050 1100 1150 1200
Annealing Temperature (°C)
J. Sol-Gel Sci. Techn. 32 (2004) 345-348
J. Non-Cryst. Solids, 345-346, (2004), 570-574.

Low-frequency Raman spectra
SiO 2 : Mn 2+
Suprasil
Intensity (a.u.)
0 ppm
200 ppm
500 ppm
-100 -50 0 50 100
Raman shift (cm -1 )
J. Non-Cryst. Solids, 243, (1999), 209

Duval et al., Phil. Mag. B 77 (1998)
2.24 nm
11.1 nm
2.9 nm
Suprasil
undoped
Mn 2+ 500 ppm
0 20 40 60 80
ω (cm -1 )

Bioactive Ceramics
Need for improved bone replacement materials
Bioactive ceramics
Crystalline : HAP Amorphous : Bioglass ®
Control of bioactivity and new functions through
- doping
- control of porosity

Bioglass ® (L.L. Hench et al.)
bioactive
Inert/fibrous
capsule
Resorbable
10-30 d
Na 2 O-CaO-P 2 O 5 -SiO 2
Bioactivity = function (composition)
Sr – doped glasses

Sol-Gel elaboration of doped bioactive glasses
Ca(NO 3 ) 2 ,4H 2 O
Si(OEt) 4
O=P(OEt) 3
Monolith
(Ca,P,Si) sol
Gel
Doping : + Sr(NO 3 ) 2
Reflux @ 85 °C Drying @ 60°C
Powder
Treatment
24 h @ 700 °C

Mesoporous Bioactive glass
monoliths
250,00
Adsorption
Desorption
200,00
Volume (cc.g -1 )
150,00
100,00
50,00
1.5 cm
0,00
0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00
P/P0
SSA between 70 and 150 m 2 /g

150 °C
450 °C
10 nm 15 nm
600 °C
700 °C
20 nm 15 nm

In vitro assays
└►In vitro assays allow important evaluation for the bioactivity of glasses
Immersion in
biological fluids
(DMEM) for
varying periods
:
up to 4 days
soaking
Glass particles
are embedded in
resin
Samples are cut into thin
sections 1 µm thick
Micro-PIXE-RBS
characterization

Ion and electron beams methods
Ion beam analysis at the micrometer scale
Micro-beam lines
PIXE : Particles Induced X-ray Emission – Multi-elementary analysis
Resolution : 1 µm at 50 pA
Experimental set-up
Si(Li) diode at 135°
Data Treatment
Gupix code
Concentrations measurements : Z > 11 (Na), sensitivity ≈ 1 µg/g
Elemental maps : 10x10 µm 2 –2x2 mm 2
Major elements
Trace elements
Ca, P, Mg, Si, Zn, Sr, K, Na, S …

Ion and electron beams methods
Ion beam analysis at the micrometer scale
Micro-beam lines
RBS : Rutherford Backscattering Spectroscopy
Elastic diffusion of the incident ion by nucleus in the target (Coulomb interaction)
Experimental set-up
Si diode at 135°
Data Treatment
SimNRA code
Rumpin code
Resolution : 1 µm at 50 pA
Stoechiometric : Z > 5 (B) ; C, N, O….
Sample weight, irradiation damages
Deposited charge (to calculate concentrations with PIXE)

Experimental device: the CENBG microbeam line
Ion source
H + , He +
Singletron electrostatic accelerator
Proton beam of 1.5 MeV energy; ∆E/E = 2.5x10
500 pA intensity
Size of the spot: 1 µm m x 1µm1
10 ─5
Experimental set up
Collimator
Russian quadruplet
PIXE
STIM
Switching magnet
Collimator
Electrostatic
scanning plates
RBS

PIXE-RBS study of interactions
SiO 2 75 % -CaO 25 % glass
Si
Ca
P
After 15 minutes of interaction

Si
Ca
P
Mg
After 1 hour of interaction

Influence of doping 5 % Sr
Si
Ca
P
4 days
Sr
Mg
-Doped glass reacts more slowly
-The Ca/P peripherical phase is still present after 4 days

Evolution of Ca/P ratio in the periphery
Un-doped glass
5 % Sr-doped glass
Time (days)
Time (days)
Chem. Mat. 20 (2008) 4969

SiO 2 -CaO 5 days

SiO 2 -CaO-P 2 O 5
5 days
J. Phys. Chem C 112, (2008) 9418

Sr 2+ delivery in solution
15
Concentration (ppm)
10
5
0
0 2 4
Interaction time in DMEM (days)

Conclusions
Flexibility of the process
NEW MATERIALS
Better dispersion
HIGH HOMOGENEITY
Doping
STRUCTURAL MODIFICATION
Doping species
NEW FUNCTIONALITIES

Acknowledgements
Université Clermont-Ferrand
E. Jallot
J. Lao
L. Courthéoux
J. Soulie
Université Lille
S. Turrell
C. Kinowski
M. Bouazaoui
B. Capoen
Université Paris 7
J.M. sautier
S. Loty
University Trento
M. Ferrari
Université Bordeaux
CENBG
P. Moretto
FNS & FRT LuminiX and LuNaTIC, ANR PNANO 2005 & 2006, INSERM Pro A for funding