X-Ray Interface Science Michael Bedzyk Materials Research Science and Engineering Center (MRSEC) Institute for Catalysis in Energy Processes (ICEP) International Institute for Nanotechnology (IIN) Center for Electrical Energy Storage (CEES) Synchrotron Research Center (SRC) Funding: NSF, DoE, Airforce X-rays: APS, NU X-ray Lab, ESRF
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X-Ray Interface Science Michael Bedzyk Materials Research Science and Engineering Center (MRSEC) Institute for Catalysis in Energy Processes (ICEP) International.
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X-Ray Interface Science
Michael Bedzyk
Materials Research Science and Engineering Center (MRSEC)Institute for Catalysis in Energy Processes (ICEP)International Institute for Nanotechnology (IIN)Center for Electrical Energy Storage (CEES)Synchrotron Research Center (SRC)
Funding: NSF, DoE, Airforce
X-rays: APS, NU X-ray Lab, ESRF
Group Party June 2013
Group breakdown: 2 postdocs, 7 graduate students
Bedzyk Group Overview: Atomic Scale View of Interfacial and Nanoscale Processes with X-Rays
X-ray Scattering and Absorption Studies of Au Nanostructures for DNA Functionalization and
Assembly
C3-SH
A10
18bp duplex Au
0 2 4 6 8 10
-0.5
0.0
0.5Ag EXAFS
Overgrown sample Ag As Synthesized sample Ag
k (A-1)
k2 *c
hi(
k)
25500 25525 25550 25575 25600
0
1
Ag XANES
AgBr Nanorod sample Ag Overgrown sample Ag Ag foil
no
rm. a
bso
rpti
on
(A
.U.)
E (eV)
X-ray Standing Wave studies
of graphen
e
DNA-NP Schematic
Nanorod growth and functionalization
Ion distribution around DNA-NPs
Incidence X-ray, 18-20 keV
In-situ interfacial structural studies of SEI formation
Nanostructured Electrodes for High Rate Li-ion Batteries
In-situ X-ray reflectivity structural studies of lithiation in anode materials
Nanoscale Electrodes for Li-Ion Batteries
Some X-ray Basics:
Wave Property Structural Info
λ = 0.1 to 10 Å wavelength E-M radiation
X-rays scatter coherently from electrons
Particle Property Compositional Info
Eϒ = 1 to 100 keV energy
Photo effect: Inner shell (K, L) ionization
XRF : Decay of excited ion to ground state by
characteristic XRF emission
X-ray Vision
Advantage: Weak interaction with matter High penetrating power
In situ analysis Buried structures
Atomic-scale resolution
Problem: Weak interaction with matter weak signal
Need very intense X-ray source
Brightest X-ray Source in Western Hemisphere
= Advanced Photon Source
relativistic electrons pass thru periodic magnetic array
Undulator Device
Argonne National Laboratory
NU
ANL
ORD
NU-ANL Carpool
Funded by US Dept. of Energy Lab
Simultaneous SAXS-MAXS-WAXS at DND-CAT/APS
Capillary Tube with flowingSample Solution
3 CCD Areal Detectors
SAXS
MAXS
WAXS
Incident X-ray Beam
$1.2 M, Just completed Upgrade
Self-assembled systems of amphiphiles
Critical packing parameter = V/AL
Spherical micelle
Fiber
Curvedmembrane
Planar membrane
hydrophilic
hydrophobic
A
V L
Applications
Template for synthesis, tissue regeneration…..
Drug delivery
Gene therapy
Cell model
Photovoltaic cells
Mimvirus(~200 nm across)
HIV virus(~150 nm across)Mouse Polyoma Virus
(~50 nm)
Crystalline lipid vesicle(~1 mm across)
(Dubois, et al., Nature 2001)
sphericalspherical
icosahedralicosahedral
Shells of different shapes
-Walby’s archaea organism-hexagonal lattice
(W. Stoeckenius J. BACTERIOLOGY, (1981))
(Iancu, et al., J. Mol. Biol. (2010) 396, 105–117)
-size and shape variability of cellular carboxysomes
100 nm
- Mixed component system
- Fluid Membranes (no internal order):
Young’s modulus (Y) = 0
Bending rigidity (κ)
- Crystalline membranes (with internal order):
Young’s modulus > 0
+
cation anion
Catanionic self-assembled membranes
cones cylinders
+ -
Cation aloneCation + anion mixture
500 nm
100nm
500 nm
Quick-freeze deep-etch TEM microscopy images
( ) ( )v
A e d q rq r r
2( ) ( )I Aq q
X-ray
Fourier Transform4 sin
q
q (nm-1)
SAXS - 1-100 nm scale features - size and shape
WAXS - molecular packing
- crystal structure
I
Small/ Wide Angle X-ray Scattering (SAXS/ WAXS)
2d
q
2q
Do an angle averaged integration
2D images from SAXS
2
3
4567
1
2
3
456
norm
aliz
ed in
tens
ity
0.012 3 4 5 6 7 8 9
0.12
q(A-1)
1D graph of intensity vs q
q (Å-1)
X-Ray
Vesicles or membranes flowing freely in solution
SAXS/WAXS Data Processing
+3 Cation and -1 anion mixture vesicles Porod Power Law
α = 2 2D platelet
5.3 nm Fit the data with a bilayer model to obtain thickness
Model fit of bilayer structure
3.8 nm
2.1 nm
cation
Cation only
+3 Cation and -1 anion mixture vesiclesCation alone
α = 2
Hexagonal lattice
Area/ molecule = 0.197 nm2
0.477 nm
Electrostatic attraction induces crystallization of tails
WAXS
Packing of tails 19
Molecular packing within membrane
d = 2π/q = λ/2sinθ = 0.413 nm
- Crystal structure can change morphology
- Molecule flow rate across membrane can be controlled by packing density and membrane thickness
- Hydrophobic drugs encapsulated inside membrane
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Why do we want to control membrane crystal structures?
- Can we control the crystal structure?
- Can we control the shape of the vesicles or membrane morphology?
Play with electrostatics!
• Change pH to change effective charge of head groups.
• Change tail length to change dipolar van der Waals attraction
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Questions
What a new student in the Bedzyk group might expect to be involved with while pursuing their
PhD • Gain an expertise with general x-ray techniques and
experimental design
• Learn fundamental materials science/ chemistry/ physics/ biology relevant to the systems they are studying (interdisciplinary research)
• Take measurements at the Advanced Photon Source and help develop the Dupont-Northwestern-Dow beamline (sector 5)
• Understand atomic-scale structure and how it applies to desirable materials properties