An Introduction to Neutron Scattering - Spallation Neutron Source
An Introduction to Neutron Scattering - Spallation Neutron Source
An Introduction to Neutron Scattering - Spallation Neutron Source
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4<br />
R*Q z<br />
10 -7<br />
10 -8<br />
10 -9<br />
1.3% PEG lipid<br />
in lipids<br />
<strong>Neutron</strong> Reflectivities<br />
Pure lipid<br />
Lipid + 9% PEG<br />
4.5% PEG lipid<br />
in lipids<br />
0 0.05 0.1 0.15 0.2 0.25<br />
Q z [Å -1 ]<br />
Polymer-Decorated Lipids at a Liquid-Air Interface*<br />
mushroom-<strong>to</strong>brush<br />
transition<br />
*Data courtesy of G. Smith (LANSCE)<br />
9.0% PEG lipid<br />
in lipids<br />
neutrons see contrast between<br />
heads (2.6), tails (-0.4),<br />
D 2 O (6.4) & PEG (0.24)<br />
x-rays see heads (0.65), but all<br />
else has same electron density<br />
within 10% (0.33)<br />
SLD [Å -2 ]<br />
Interface broadens as PEG<br />
concentration increases - this is<br />
main effect seen with x-rays<br />
R/R F<br />
8 10 -6<br />
6 10 -6<br />
4 10 -6<br />
2 10 -6<br />
0<br />
10 1<br />
10 0<br />
10 -1<br />
10 -2<br />
10 -3<br />
SLD Profiles of PEG-Lipids<br />
Black - pure lipid<br />
Blue - 1.3% PEG<br />
Green - 4.5% PEG<br />
Red - 9.0% PEG<br />
40 60 80 100 120 140 160<br />
Length [Å]<br />
X-Ray Reflectivities<br />
Lipid + 9% PEG<br />
Pure lipid<br />
0 0.1 0.2 0.3<br />
Q<br />
z<br />
0.4 0.5 0.6
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