Adhesion forces between TiO2 nanoparticles
Adhesion forces between TiO2 nanoparticles
Adhesion forces between TiO2 nanoparticles
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Force measurements <strong>between</strong> TiO 2<br />
<strong>nanoparticles</strong> forming agglomerates<br />
Samir Salameh<br />
Lucio Colombi Ciacchi<br />
Lutz Mädler<br />
Fachbereich Produktionstechnik, Universität Bremen<br />
Paolo Facci<br />
S3 national center of CNR-INFM, Modena<br />
Samir Salameh<br />
1
Outline<br />
Nanoparticle synthesize and AFM implementation<br />
Results of adhesion force <strong>between</strong> pure TiO 2 aggregates<br />
Results on modeling<br />
Conclusion<br />
Samir Salameh<br />
2
Particle synthesis with flame spray<br />
pyrolysis<br />
2 cm<br />
Mädler et al. (2002) Jou. of mat. Res.,<br />
17, 1356-1362<br />
Samir Salameh<br />
3
Filmstructure off TiO 2 aggregates on<br />
Mica<br />
20 µm 500 nm<br />
Samir Salameh<br />
4
Idealized force measurements on<br />
<strong>nanoparticles</strong><br />
Butt et al. (2005) Surface Science Reports 59 1-152<br />
Samir Salameh<br />
5
<strong>Adhesion</strong> force <strong>between</strong> TiO 2<br />
nanoparticle aggregates<br />
3<br />
2<br />
1<br />
Force in nN<br />
0<br />
-1<br />
-2<br />
-3<br />
-4<br />
-5<br />
retraction<br />
approach<br />
0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5<br />
seperation in µm<br />
Samir Salameh<br />
6
<strong>Adhesion</strong> force <strong>between</strong> TiO 2<br />
nanoparticle aggregates<br />
3<br />
2<br />
1<br />
Force in nN<br />
0<br />
-1<br />
-2<br />
-3<br />
-4<br />
-5<br />
retraction<br />
approach<br />
0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5<br />
seperation in µm<br />
Samir Salameh<br />
7
<strong>Adhesion</strong> force <strong>between</strong> TiO 2<br />
nanoparticle aggregates<br />
3<br />
2<br />
1<br />
Force in nN<br />
0<br />
-1<br />
-2<br />
-3<br />
-4<br />
-5<br />
retraction<br />
approach<br />
0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5<br />
seperation in µm<br />
Samir Salameh<br />
8
<strong>Adhesion</strong> force <strong>between</strong> TiO 2<br />
nanoparticle aggregates<br />
3<br />
2<br />
1<br />
Force in nN<br />
0<br />
-1<br />
-2<br />
-3<br />
-4<br />
-5<br />
retraction<br />
approach<br />
0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5<br />
seperation in µm<br />
Samir Salameh<br />
9
Distribution of the adhesion force with R<br />
x̄ = 3,6<br />
Standard dev.= 1,97<br />
n = 1025<br />
Samir Salameh<br />
10
Mean and standard deviation increase<br />
for the last set of measurements<br />
6<br />
mean value of force measurements<br />
5<br />
4<br />
Force in nN<br />
3<br />
2<br />
1<br />
0<br />
0-200 200-400 400-600 600-800 800-1000<br />
set of 200 measurements<br />
Samir Salameh<br />
11
Particle number increase with<br />
increasing number of measurements<br />
n < 10 n > 50<br />
1 µm<br />
2 µm<br />
Samir Salameh<br />
12
Minimum force for breaking chains<br />
Rong, Mädler et al. (2004) Nanoletters,<br />
4, 2287-2292<br />
Samir Salameh<br />
13
MD modelling of TiO 2 particle seperation<br />
Force in nN<br />
Distance in nm<br />
Samir Salameh<br />
14
Iron in TiO 2 lattice changes<br />
surface properties<br />
40<br />
30<br />
TiO 2<br />
TiO 2<br />
10% Fe<br />
20<br />
10<br />
Zeta-Potential<br />
0<br />
-10<br />
-20<br />
-30<br />
-40<br />
Teoh et al. (2007) Catalysis today,<br />
120, 203-213<br />
3 4 5 6 7 8 9 10 11<br />
PH-Wert<br />
Samir Salameh<br />
15
Iron atoms prefer the outer levels<br />
Samir Salameh<br />
16
conclusion<br />
Method for analyzing adhesion force <strong>between</strong><br />
<strong>nanoparticles</strong><br />
Particles migrate from layer to the AFM tip<br />
Experimental data and Modelling fits well<br />
Samir Salameh<br />
17
outlook<br />
Statistical analysis of TiO 2 10% Fe force measurements<br />
Validation of resultes with a rutile single crystal in<br />
mikrometer size<br />
Perform fishing experiments on TiO 2 monolayers with<br />
different particle sizes<br />
Samir Salameh<br />
18
Force measurements <strong>between</strong> TiO 2<br />
<strong>nanoparticles</strong> forming agglomerates<br />
Samir Salameh<br />
Lucio Colombi Ciacchi<br />
Lutz Mädler<br />
Fachbereich Produktionstechnik, Universität Bremen<br />
Paolo Facci<br />
S3 national center of CNR-INFM, Modena<br />
Samir Salameh<br />
19
Back up<br />
http://www.nyah.ch/fun/archiv/backup.jpg<br />
Samir Salameh<br />
20
SEM picture from Si 3 N 4 tip<br />
Samir Salameh<br />
Samir Salameh<br />
21<br />
21
AFM force curve <strong>between</strong> TiO 2<br />
<strong>nanoparticles</strong><br />
3<br />
2<br />
1<br />
0<br />
Force in nN<br />
-1<br />
-2<br />
-3<br />
-4<br />
-5<br />
-6<br />
-7<br />
-8<br />
-9<br />
retraction<br />
approach<br />
-10<br />
0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5<br />
seperation in µm<br />
Samir Salameh<br />
22
Minima to maxima analysis of<br />
force curves<br />
Samir Salameh<br />
23
EFTEM analysis of TiO 2 10% Fe<br />
Iron TiO 2<br />
Samir Salameh<br />
24
EDX analysis of TiO 2 10%Fe<br />
Samir Salameh<br />
Samir Salameh<br />
25<br />
25
Primary particles size of TiO 2 and Fe/TiO 2<br />
26<br />
26<br />
24<br />
TiO 2<br />
10% Fe<br />
TiO 2<br />
Partikelgröße d BET<br />
in nm<br />
22<br />
20<br />
18<br />
16<br />
14<br />
12<br />
10<br />
8<br />
1.0 1.5 2.0 2.5<br />
Verhältnis Durchflussrate Präkursor/Sauerstoffstrom<br />
Samir Salameh<br />
Samir Salameh<br />
26
Change language