Small-Angle Neutron Scattering - Kfki

Contrast variation on FFs:
separate homogeneous particles
Biocompatible FFs with maghemite coated by citric ions (0.2 nm) in water.
Coulomb interaction compensated (NaCl addition). Magnetic interaction compensated (ϕ m ~ 1%).
I c (q)
(negligible magnetic scattering)
Mitglied in der Helmholtz-Gemeinschaft
I(q), cm -1
100
10
1
0.1
0.01
1E-3
1E-4
0 % D2O
70 % D2O
80 % D2O
90 % D2O
95 % D2O
100 % D2O
I s (q)
(matched nuclear scattering)
0.1 1
q, nm -1
R g
2
110
100
90
80
70
60
50
characteristic nuclear radius
R N ~ 10 nm
0 2 4 6 8 10
∆ρ~
−1
( ) ×
Increase in apparent particle size
because of residual Van der Waals interaction
(non-uniform surface charge distribution)
• Avdeev, M.V., Dubois, E., Mériguet, G., et al., J. Appl. Cryst. 42 (2009) 1009-1019
characteristic magnetic radius
R M ~ 7.2 nm
10
-10
cm
2