![Page 1: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/1.jpg)
Hans Wolfgang Spiess
Max-Planck-Institut für PolymerforschungMainz, Germany
“NMR Spectroscopy of Polymers”Tutorial
ACS National Meeting
New Orleans, April 6, 2008
Overview of NMR of Bulk Polymers
![Page 2: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/2.jpg)
Overview of NMR of Bulk Polymers
Introduction •
Configuration, Conformation •
Local Structure & Dynamics •
Phase Behavior •
Supramolecular Organization •
Conclusions •
Basics
Chain Branching
Amorphous & Crystalline Polymers
Core Shell Structures
Functional Polymeric Systems
Scattering and NMR
![Page 3: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/3.jpg)
Chemical Shift
Ranges for
Organic
Compounds
Isotropic Anisotropic (13C)
Analogous for 2H quadrupole coupling
![Page 4: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/4.jpg)
Structure and Dynamics from Solid-State NMR
Dipole-Dipole
Coupling
i
jθij
rij
B0 ( cos )Drij
iji j∝ -3 13
12
2θγ γ
⋅
Orientation of internuclear vectorDistance between nuclei
1H-1H1H-13C 13C-13C1H-15N
20 15 10 5 025
coupling strength [kHz]
Typical
pairs
of nuclei
Structure
Dynamics
2H quadrupolecoupling
![Page 5: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/5.jpg)
static
1 kHz
2 kHz
4 kHz
8 kHz
15 kHz0 4 8-12 -4 12-16
frequency [kHz]16-80 1 2 3 4 5 6 7
time [ms]
Solid State NMR Spectra
2H static spectra
13C MAS spectraSpin
nin
g f
requen
cy
2H quadrupole coupling
![Page 6: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/6.jpg)
Magic-angle spinning (MAS)
rotor is spun around an axis inclined at an angle of θm =54.7° with respect to B0 .
spatial part of interaction tensor averaging by
fast rotationresulting average tensor
How does MAS work ?
in terms of coordinate transformations:
212 (3cos 1)θ − 21 1
2 2sin cos(2 2 ) sin(2 ) cos( )R Rt tβ ω γ β ω γ− − −
rotor modulations with frequencies 2ωR and ωR
θm
ωR
B0
ωR
θ
θmωR
B0 B0 B0
![Page 7: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/7.jpg)
Polyolefin Branching
Short (SCB)< 30 C
Long (LCB) > Me ≈
270 C
pronounced effect on viscosity &
melt processability
![Page 8: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/8.jpg)
MAS-NMR in Melts: Very Low Branch Contents
‘Linear’
PE
∗ α∗B2
∗
α
∗B2 α α
Quantification of 7–8 branches per 10 000 COptimised solution
NMR:
50,000 to 2,000,000 scans (up to 60 days!)Optimised melt-state NMR: 21,500 scans (13 h)
Site SNR Content
per 1000 C
*B2 4.5 0.07
* 3.7 0.05
α 9.4 0.08
Sample:R.H. Grubbs, Caltech
Macromolecules 37, 813 (2004), Macromol. Chem. Phys. 207, 382 (2006).
![Page 9: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/9.jpg)
13 C –
NMR: Conformational Effects
Potential Energy
Polymer Chain
Gamma -
gauche effect:-
5,2 ppm in alkanes
Sensitivity of
13C Chemical Shifts
on Conformation
:
42 40 38 36 34 32 30 28 26 24 22
13C NMR spectrum of PE
Crystalline regions:all-trans
Non-crystallineregions: gauche
![Page 10: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/10.jpg)
Conformational Effects on 13C Chemical Shifts
![Page 11: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/11.jpg)
Self-Assembly and Molecular Dynamics of Peptide- Functionalized Polyphenylene Dendrimers
Short polypeptides (n < 16)High order of columns,
Low order of peptide chains
Long polypeptides (n > 20)Low order of columns,
High order of peptide chains(α-helices)
X-ray Scattering:columnar order
Solid state NMR:Peptide conformation
176.3 ppm 172.4 ppm
13C=O
PLys
G2
F16
N16
G2
F16
N58
α -
helix β -
sheet
![Page 12: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/12.jpg)
Overview of NMR of Bulk Polymers
Introduction
•
Configuration, Conformations •
Local Structure & Dynamics
•
Phase Behavior •
Supramolecular Organization •
Conclusions •
Basics
Chain Branching
Amorphous & Crystalline Polymers
Core Shell Structures
Functional Polymeric Systems
Scattering and NMR
![Page 13: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/13.jpg)
Motional averaging effects
( ) 2 ( ) ( ) ( ) ( )12 (3cos 1)(3 )ij i j i j
ijD θ= ⋅ − −D Z ZH I I I I
Motional averaging:2 !21
20 0
(3cos 1) sin 0d dπ π
θ ϕ θ θ− =∫ ∫
221
2 (3cos 1)(3 )2 (2 1)Q
e qQI I
θ= ⋅ − − ⋅− ⋅ Z ZH I I I I
h
2 212 (3cos 1 sin cos(2 ))δ θ η θ ϕ= ⋅ − − ⋅CS ZH I
Solid crystal
Plastic crystalLiquid crystal
Anisotropic Chemical Shift
Dipole-Diplole Coupling
Quadrupole Coupling
order parameter Sij :
)1cos3(S 221
ij −θ=
![Page 14: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/14.jpg)
Motional averaging effects
Basics: Two site jumps
(analogous to chemical exchange)
Calculated NMR line shapes resulting from interchange between two NMR frequencies.
Δ
: coupling strengthΩ
: exchange rate
The numerical values apply to 2H NMR of deuterons in C-H bonds
fast
intermediate
slow
ultraslow
![Page 15: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/15.jpg)
Two-site jumps: CSA
1H powder spectrumof H2 O molecules
in crystalline CaSO4 ·2H2 O
δ
1jump
jump
kδ δ τ= = ⋅m
m
m
m
m
m
m
Two-site jump in solid: Different frequencies depending on orientation.
Result in fast motion limit:Averaged interaction tensor
Line shape analysis yields both:Timescale and geometry of motion
![Page 16: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/16.jpg)
Two-site jumps: CSA, DDC and QC
Example: Phenyl180° ring flip:
Reorientation C-H bondsby β
= 120°
Averaged principal axes (1), (2) and (3)
δ = 5/8 δ ; η
= 0.6
Single transition Pake pattern
Anisotropic Chemical Shift
QuadrupoleCoupling
![Page 17: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/17.jpg)
The “solid echo”
experiment
0 0.5 1-0.5-1ω/δ
x
xx
sampling (“dwell”) time
deadtime
Large spectral width (> 250 kHz) requires short dwell and dead times (< 4 µs).
x y
Overcoming the dead-time problem by echo experiments:
spin (“Hahn”) echo solid (“Solomon”) echo
refocuses “linear-spin” interactions refocuses “bilinear-spin” interactions
![Page 18: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/18.jpg)
Motions in the “solid echo”
experiment: Increased dynamic range
Absorption spectra:Line shape changes within one order of magnitude
Solid echo spectra:Line shape changes over several orders of magnitude,
But: loss of signal!
![Page 19: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/19.jpg)
NMR line shapes conveniently calculated by NMR Weblab
http://weblab.mpip-mainz.mpg.de/weblab/weblab.html
![Page 20: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/20.jpg)
NMR Weblab: How to use it
http://weblab.mpip-mainz.mpg.de/weblab/weblab.html
![Page 21: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/21.jpg)
NMR Weblab: Example phenyl flip
http://weblab.mpip-mainz.mpg.de/weblab/weblab.html
![Page 22: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/22.jpg)
Inhomogeneous and homogeneous line broadening
...
Inhomogeneous:CSA, quadrupolar, dipolar two-spin
Due to spin-spin couplings the energy levels of single transitions (resonance lines) are no longer degenerate, but
split into a multitude of levels
Overall resonance consists of indiviual sharp lines and
represents the sum over all different orientations
Homogeneous:dipolar multi-spin
Similar distinction ifwhole line shapes are superimposed due to a distribution of
• different structures, or• different rates, or • different geometry of
motion
![Page 23: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/23.jpg)
Example of heterogeneous rate distribution
narrow broad
distribution
rigid limit
rapid exchange
Superposition of line shapes for different rates
![Page 24: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/24.jpg)
2D-Exchange-Spectroscopy:
Simplicity
Pulse Sequence Spectra
Determine geometry and time scale of motions directly and in real time
![Page 25: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/25.jpg)
Geometry
of Chain Motion in Polymers
POM (crystalline) PEO(disordered) PVAc
(amorphous)
13C 2D Exchange NMR Spectra of Polymers with Different Degrees of Disorder
![Page 26: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/26.jpg)
Helical jumps in polymer crystallites: POM
Timescale and Geometry of Motion
![Page 27: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/27.jpg)
Chain Folding, Chain Diffusion and Drawability
Chain motionMorphology Chain diffusion
Local Collective
Ordered Disordered
SolutionCrystallized
MeltCrystallized
DrawabilitySample:
UHMW-PE (Mw =3.4 M)
Solution
Crystallized:
Drawable
Melt
Crystallized:
Not
Drawable
![Page 28: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/28.jpg)
Timescales of Molecular Dynamics Accessible by NMR
Averaging of dipole-dipole couplings, as detected by spinning sideband experiments: C-H, N-H: REREDOR, REPT-HDORH-H: double-quantum
Destructive interference effects: reduction and loss
of NMR signal
Change of anisotropic interactionsduring experimental “mixing time”:exchange NMR
experiments2H, 13C, 15N: 2D, CODEX etc.
Spin-lattice relaxation:dipole-dipole coupling, quadrupole coupling,anisotropic chemical shift
fast
10010-110-210-310-410-510-610-710-810-9
slowvery fast intermediate
motional correlation time [seconds]
![Page 29: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/29.jpg)
Conformational Dynamics at the Glass Transition
Potential Energy
Gamma - gauche effect:- 5,2 ppm in alkanes
Polymer Chain
Sensitivity of 13C Chemical Shifts
on Conformation :
![Page 30: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/30.jpg)
Chain Dynamics of Atactic Poly(propylene) at the Glass Transition
Correlation Times of Chain Motionfrom different NMR experiments
All data fit on a singleWLF - curve
Conformational dynamics from 2D 13C MAS NMR
Rotational dynamics from 2D 2H NMR
Geometry: ReorientationalAngle Distribution
Conformational transitions,but no defined geometry
![Page 31: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/31.jpg)
Structure Schemes of Syndiotactic
and
Isotactic
Poly-(Methyl-Methacrylate)
syndiotactic isotactic
ω33ω33
localchain-axis
localchain-axis
schematicstructure
crystal structures
schematicstructure
NMR probes local chain-axis
through ω33
n-alkyl-methacrylates contain extended chain segments
Example:PMMA
![Page 32: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/32.jpg)
a-PEMA: Two-step Randomization of Chain Motion
180°
CO
13
ω33<10°
ω22
ω11
180°C
O13
0°
-
180°
180°
CO
13 ω
50°ω
400 K
405 K
411 K
433 K
472 K
394 K
250 200 150 100
298 K
ω
ω
ω22
ω33
ω11
1D 13C NMR: experimentsimulation
melt
melt
melt
gla
ss
Tgrigid + fractionalsidegroup flips
+ anisotropicchain motion
+ randomizationof chain motion
Tg = 354 K
![Page 33: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/33.jpg)
tem
pera
ture
s-PEMA: Conformation and Conformational Dynamics
(mr)
(rr)
CH3 (main chain)
CD3(side chain)
(mm)
T = 303 K
t.tt.g / g.t
g.g
t.g / g.tg.g / g.g
g.g
35 30 25 20 15 10 ppm
[ [
Tg - 50 K
s-PEMA
T = 353 K
Tg + 65 K
Tg = 354 K
T = 418 K
35 30 25 20 15 10 ppm
(mm)(mr)
(rr)
13C MAS NMR
![Page 34: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/34.jpg)
Separation of Dynamic Timescales in PEMA-Melts
Correlation Times from NMR, PCS, Dielectrics
Tg = 338K
α-Relaxation(WLF)
β-relaxation(Arrhenius)
NMR: spatial randomisation
(tI, WLF)
NMR: confromational relaxation
NMRPCSDielectric
2.2 2.4 2.6 2.8 3.0 3.2 3.410-8
10-6
10-4
10-2
100
102
2.0
1000 / T [K-1]
time
[s]
Difference in time scale (factor 50):consistent with length scale 7 repeat units
Tc
![Page 35: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/35.jpg)
Intersegmental
Order in Poly(methacrylates): WAXS(LVDW)
PMMA
PEMA
PBMA
PHMA
Inte
nsity
[a.u
.]
q [nm-1]0 10 20
II/I
WAXS-DataIII
(VDW)
III
?syndiotactic
PEMA
main chain
side chains
dI
dIII
d0
IIId
dII
„layered nano aggregates"
isotacticPEMA
main chains
side chains
monolayer
bilayer
X-Ray patternsreminiscent of
stiff macromoleculeswith
flexible sidechains
X-R
aySca
tter
ing
0
0.4
0.8
1.2
1.6
0 2 4 6 8 10 12# sidechain carbon atoms
Brag
gdi
stan
ces
d [n
m]
I
II
III
(VDW)
(LVDW)
Bragg-Distance
intra chain
inter chain
inter layer
![Page 36: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/36.jpg)
2D DECODER NMR for Ordered Systems
Example: Biaxially stretched PET
2D exchange with sample fliprather than molecular motion
![Page 37: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/37.jpg)
Recoupling CSA: CODEX
CODEX: Centreband-Only Detection of ExchangeApproach: Recoupling the chemical-shift anisotropy (CSA) under MAS
0 1 N/2
~ ~
N/2+n
CP
DD DD
[ ]N/2-1 [ ]N/2-1
tm AQ
nτR
+ + + +- - --
CP DD
exchange during tm ?Complete refocusing of CSA only if there is no exchange during tm !
Advantages:High spectral resolution, short measuring time compared to 2D exchange NMR
θm
ωR
B0
![Page 38: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/38.jpg)
0 1 2 3 4 5 6 7 8 9 10 11 120,0
0,1
0,2
0,3
0,4
0,5
0,6
δ N τR / π
10°/170°
20°/160°
30°/150°
40°/140°
50°/130°
70°-110°
60°/120°
DMST = 288 K
Exc
hang
e in
tens
ity
tmtm
CODEX: reorientation angle
CODEX build-up curves
exchange intensity for a given mixing time depends on the overall duration of recoupling
shape of the curves depends significantly on the reorientation angle
![Page 39: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/39.jpg)
Overview of NMR of Bulk Polymers
Introduction
•
Configuration, Conformations •
Local Structure & Dynamics •
Phase Behavior •
Supramolecular Organization
•
Conclusions •
Basics
Chain Branching
Amorphous & Crystalline Polymers
Core Shell Structures
Functional Polymeric Systems
Scattering and NMR
![Page 40: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/40.jpg)
Phase Separation Probed by Spin diffusion
NMR spectra
Morphology and1H magnetization
MZ
selection spin diffusion
x
A B A
inte
nsi
ty
ωCS
spin diffusion time tm
A B A
B
AA
BA B
NMR spin diffusion experiment
selection diffusion
tm
Chemical shift filters (e.g. DANTE): spectral selection
Dipolar filters (e.g. SR-12): motional selection
![Page 41: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/41.jpg)
Domain Sizes in Phase Separated Polymers
Both Components RigidRigid and Mobile Components
![Page 42: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/42.jpg)
Spin Diffusion in 2D Wideline
Separation Spectra
Interface
spin diffusion
![Page 43: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/43.jpg)
Investigating core-shell particles
structure and particle size can be determined
0 10 20 30 40 50
1.0
0.8
0.6
0.4
0.2
0.0
tm [ms 0.5 ]0.5
I/I0
38 nm76 nm113 nm
(t ms)1/2
d Particle =
contact surface: S source volume: V
withS/V Deff tmSπ
= 2eff
DA DBDDA
=+ DB
magnetization source
magnetization drain
initial slope
I/ I0
1.0
0.8
0.6
0.4
0.2
0.00 5 10 15 20 25
tm [ms0.5 ]0.5
![Page 44: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/44.jpg)
Overview of NMR of Bulk Polymers
Introduction
•
Configuration, Conformations •
Local Structure & Dynamics •
Phase Behavior
•
Supramolecular Organization
•
Conclusions •
Basics
Chain Branching
Amorphous & Crystalline Polymers
Core Shell Structures
Functional Polymeric Systems
Scattering and NMR
![Page 45: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/45.jpg)
Key Elements of Supramolecular Assemblies
shapeπ−π
stac
king
C 1 2 H 2 5
C 1 2 H 2 5
C 1 2 H 2 5
C 1 2 H 2 5
C 1 2 H 2 5
C 1 2 H 2 5
H-bonds
C H2713
N
N
HaO
N
C H27Hd
ON
Hc Hb Hb Hc
O N
NHa
O
N N
Hd
13
n
surfac
es
Challenge: Elucidate Noncrystalline
Structures
![Page 46: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/46.jpg)
Scattering
X-ray- or neutron-scattering
Incident Scattered
Wave
Scattering Diagram / (Reflections)
1/d
r
r
rf- irradiation
DoubleQuantumCoherence
NMR Spectrum
1/r3
Double Quantum NMR
Analogy:In both cases: coherent superposition
of signals from spatially separated centers
![Page 47: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/47.jpg)
1H NMR spectra in solid and liquid state
60 40 20 0 -20 -40 kHz-60
5 0 kHz
20 10 0 kHz
static
30 kHz MAS
solution
θm
ωR
Magic-AngleSpinning (MAS)
rapid isotropictumbling
3 kHz4HRMAS
partialmobility
increasing
spectral
resolution
rigidsolid
dipolarbroadening
high magneticfield: 700 MHz
![Page 48: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/48.jpg)
Dipolar DQ Spectroscopy of a Spin-Pair under MAS
Reconversion DetectionEvolution
t1
Excitation
texc = nexctR
y -yx -x
nexc
y -yx -x
nrec=nexc
x τR
trec = nrectR
θm
ωR
i
j
θij
B0
rij
Dipole-Dipole Coupling:
$ $ $, ,H R T= ⋅2 0 2 0
Space Spin
t2Recoupling Recoupling
![Page 49: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/49.jpg)
Line Narrowing in Solid-State NMR
Hamiltonian of Dipole-Dipole Coupling:
i
j
θij
B0
$ ( cos ) ( $ $ $ $ ), ,Hr
I I I Iij
ij i j Z i Z j i j∝ − − ⋅1
3 1 3312
2 θ γ γ
$ $ $, ,H R T= ⋅2 0 2 0
Space Spin
Magic Angle Spinning:
$,R2 0 0 ωR
θ
θm
ωR
θm
ωR
B0 B0 B0 B0
R R
RF Irradiation:
$,T2 0
00 tC
-x y -y x
tτ ττ τ2τ τ ττ τ2τ τ ττ 2τ
-x y -y x -x y -y
tC
0 t
t
t
(CRAMPS)
(Recoupling)HD,eff.
x y -y-x
τ τ
x y -y-x
τ τ
x y-x
τ
![Page 50: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/50.jpg)
Signal build-up versus rotor-encoding
I
S
REDOR scheme
I
S
t1
Rotor-
encoded
REDOR scheme
trcpl
trcpl trcpl
Two alternative
concepts for measuring recoupled interactions:
• following the signal intensity as a function of the recoupling time (resulting in build-up
or dephasing curves)• recording rotor-encoded
signal (resulting in MAS sideband patterns)
![Page 51: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/51.jpg)
Rotor-encoding of dipolar Hamitonians
IS0
R
D 2 2 sin 2 sinΦ = − β γω
Recoupled
dipolar Hamiltonian:
with dipolar “phases” for first recoupling period:
IS1 R 1t
R
D 2 2 sin 2 sin( t )Φ = − β ω + γω
and for “rotor-encoded”second recoupling period:
t1 2nd recouplingperiod
1st recouplingperiod
ωR
ωR
0Φ0Φ
0Φt1Φ
Leads to Amplitude
Modulation
of Signal
and hence, Sidebands
![Page 52: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/52.jpg)
REDOR-type curves and sideband patterns
ω/ωR
-3 3-1 1 5-5
(i)
(ii)
(iii)
0 1 2 3
DISt rcpl
/ 2π
Inte
nsi
ty (
a.u.)
0.5
0.4
0.3
0.2
0.1
0
(i)(ii)
(iii)
Build-up curves decay
HDOR sideband patternsrobust:
Multispin effects: additional sidebands
Multispin effects and relaxation
![Page 53: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/53.jpg)
Multiple-quantum NMR methods: investigating (supra)molecular
structure
H H''H'
H
H'H''
CH' CH2CH
O
OCH2
H'H
H
H'
rHH
H
H'
rNH
5 3 1 –1 –3 –5
1 H-1 H
hom
onuc
lear
1 H-13
C/15
N h
eter
onuc
lear
internuclear proximities,chemical
shifts
and π-shiftsinternuclear distances
π
7 -79 -9
5 3 1 –1 –3 –57 -79 -9
0.21 nm
0.24 nm
0.27 nm
0.16 nm
0.18 nm
0.20 nm
molecular
dynamics
![Page 54: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/54.jpg)
Multiple Hydrogen Bonds in Natural and Synthetic Systems
DNA
Supramolecular polymers via hydrogen bonds
C H2713
C H2713
N
NN
Hd
Hb Hb Ha
N
N N
N O
Hd
O
HaO
Hc
N
O
Hc
n
R.P. Sijbesma, E.W. Meijer et al., Science, 1997:Thermoreversible linkages through quadruple hydrogen bonding
C H2713
N
N
HaO
N
C H27Hd
ON
Hc Hb Hb Hc
O N
NHa O
N N
Hd
13
n
Keto form Enol form
Watson-Crickbase pairs
DQ NMRspectrum
DQ NMRspectrum
![Page 55: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/55.jpg)
Heat-Induced Tautomeric
Rearrangement: 1H-1H DQ Spectra of Quadruple Hydrogen Bonds
Heating
51015single quantum ω2 [ppm]
10
15
20
25
30
ω1 [p
pm]
a b c d
b- c
b- b
C H2713
N
N
a
O
N
C H27d
ONc b b c
O N
N a O
N N
d
13
n
before heating: keto form
51015single quantum ω2 [ppm]
10
15
20
25
30
ω1
[ppm
]
a b c d
b- b
a- b
C H2713
C H2713
N
NN
d
b b a
N
N N
N O
d
O
aO
c
N
O
c
n
after heating: enol form
![Page 56: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/56.jpg)
Kinetics
of the
Tautomeric
Rearrangement
0
0.2
0.4
0.6
0.8
1
Temperature [K]
keto form
enol form
310 330 350 370 390 410 430
enol
frac
tion
TemperatureDependence
T [K]
10-3/T [K]Plot 0 2.70 2.75 2.80
-13
-12
-11
-10
lnk
375 365 355
EA = (145± 15) kJ/mol
tran
sitio
n ra
te
Arrhenius
TimeDependence
0 5 10 15 20 25
0.4
0.5
0.6
Time [h]
T = 375 Kenol form
keto form
enol
frac
tion
![Page 57: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/57.jpg)
Multiple N-H Distances in the Pyrimidinone
Form
REREDOR 24/24240 pm280 pm~ 65°
107.5REREDOR 6/6107.5 pm201 pm~ 180°
106
201
1H{15N}
recoupling: 1H - detection
-8 -4 0 4 8 ω/ωR
201
107.5
~180°
-8 -4 0 4 8 ω/ωR
280
240
~65°
REREDOR 8/8107 pm
-8 -4 0 4 8 ω/ωR
107
![Page 58: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/58.jpg)
Separator Membranes and NMR
reveal details of proton conductivityon molecular level(site-selective & non-destructive)
provide structural constraints(proton transfer mechanism ?)
![Page 59: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/59.jpg)
PVPA: poly(vinyl
phosphonic
acid)
31P NMR
phosphonic
acid units, local dynamics
1H-31P and 1H-1H NMR
hydrogen bonding
at phosphonic acid units
1H-13C NMR
segment mobilities of alkyl chains, polyvinyl backbone
1H NMR
backbone as well as mobile protons
(local dynamics)
2H NMR
primary process: orientation-dependent rate of movement:time scale and geometry (multi-site jumps)
NMR probes for local structure & dynamics
High proton conductivity under dry conditions at elevated temperatures
![Page 60: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/60.jpg)
PVPA: VT NMR motional narrowing
condensationbackbone unaffected
mobileOH groups
31P
MAS NMR1H
MAS NMR
very narrow
lines in both 1H and 31P spectra
![Page 61: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/61.jpg)
Poly(vinyl phosphonic
acid): PVPA
EA
= 25 kJ/mol2.2 2.4 2.6 2.8 3.0 3.2
-9
-8
-7
-6
-5
Log
(T2* )
1000/T (K-1) -414 12 8 4 0ppm
10 6 2 -2
2015105
-5
ppm
25
0mobile
1H -
1H DQ Spectra
281 K
-416 12 8 4 0ppm
2015105
-5
ppm
2530
0
318 K
motion frozen
**
n
POO
ODD
P-OH proton: mobile
P-OH : mobile proton, hydrogen bondedDynamics of motion involved in proton conduction
20 10 0 -10
413 K
394 K
375 K
356 K
318 K
ppm150 100 50 0 -50 -100 -150
297 K
393 K
353 K
253 K
kHz
230 K
1H MAS spectra
2H solid echo spectra
![Page 62: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/62.jpg)
PVPA: ab initio structure
(model
geometry)
Ab initio calculation based on model geometry (CPMD):
* Elucidation of hydrogen bondings and 1H chemical shift calculation:H-bonding between phosphonic acids on the same chains and between two parallel chainsMD: Proton hopping occurs along chains as well as between chains mediated by hydrogen bonds.calculated δ(P-OH) = 9.7 ppm (exp.: 10.6 ppm)
H-bonding between the chains
H-bonding along the chains
PO
![Page 63: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/63.jpg)
PVPA: Averaging of Deuteron Quadrupole
Coupling
Broad distribution of angles betweeninstantaneous O-H and C-P directions,yetQuadrupole coupling reduced by factor 10 after CPMD run of 15 ps
![Page 64: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/64.jpg)
Overview of NMR of Bulk Polymers
Introduction
•
Configuration, Conformations •
Local Structure & Dynamics •
Phase Behavior •
Supramolecular Organization •
Conclusions •
Basics
Chain Branching
Amorphous & Crystalline Polymers
Core Shell Structures
Functional Polymeric Systems
Scattering and NMR
![Page 65: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/65.jpg)
Scattering and NMR in Bulk Polymers
incoherent coherent single quantum
double quantum
D
Y
N
A
M
I
C
S
Molecular n-quasielastic n-quasielastic 2D-, 3D-, 4D- exchange
sidebands
Collective n-spin-echo 2D-exchange decay of DQC
S
T
R
U
C
T
U
R
E
Molecular WAXS, WANS chemical shift,sidebands
2D pattern,sidebands
Collective
(packing)
X-ray pole figures, SAXS, SANS
DECODER chemical shift
2D signal pattern
SCATTERING NMR
![Page 66: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/66.jpg)
Advantages of NMR:
- Selectivity, Versatility
- Detailed information on geometryand time scale of dynamics
- Large range of length- and timescales accessible
- Elucidation of supramolecularorganization
- Relation between structure, dynamics and functional behavior
- Limits not reached, e.g. microcoils
Overview of NMR of Bulk Polymers
![Page 67: Overview of NMR of Bulk PolymersOverview of NMR of Bulk Polymers. Introduction • Configuration, Conformation • Local Structure & Dynamics • Phase Behavior • Supramolecular](https://reader035.vdocuments.net/reader035/viewer/2022070809/5f08644b7e708231d421c7b6/html5/thumbnails/67.jpg)
K. Schmidt-Rohr, H.W. Spiess, Multidimensional NMR and Polymers, Academic Press, London, 1994
H. W. Spiess, Advanced Solid-State Nuclear Magnetic Resonance for Polymer Science;J. Polym. Sci. A 42, 5031–5044 (2004).
H.W. Spiess, NMR Spectroscopy, in Macromolecular Engineering, edited by K. Matyjaszewski, Y.Gnanou, L. Leibler, WILEY-VCH, Weinheim, Vol. 3, 1937-1965 (2007).
H. W. Spiess, NMR Spectroscopy: Pushing the Limits of SensitivityAngew. Chem. Int. Ed. 47, 639-642 (2008).
References