Investigation of Structure and Dynamics in

Polymeric Systems via Solid State NMR

Robert Graf

Max-Planck-Institut für PolymerforschungMainz

March 2nd, 2005

founded 1983, 450 co-workers, on campus of the University of Mainz,

interdisciplinary fundamental research of polymers

Max Planck Institute for Polymer Research

MPI-P OrganizationBoard of Directors

MaterialsScience

Knoll

Theory

Kremer

Synthesis

Müllen

Solid StateChemistry

Wegner

PolymerPhysics

Butt

ScientificScientificProject AreasProject Areas

PolymerSynthesis

SupramolecularArchitecture

Surfacesand Interfaces

Developmentof Methods

Structureand Dynamics

FunctionalMaterials

Mass Spectrometry

High Resolution NMR

Optical Spectroscopy

Thin Films

Microscopy

Polymer Analysis

Computer and Network Service

Clean Room

Mechanical and Dielectric Relaxation

X-Ray Structure Analysis

Max Planck Institute for Polymer Research

Spectros-copy

Spiess

Scientific Activities of the MPI-P Spectroscopy Group

Structure and DynamicsStructure and Dynamics Development of MethodsDevelopment of Methods

Functional MaterialsFunctional Materials Supramolecular ArchitecturesSupramolecular Architectures

Su

rface

s & In

terfa

ces

Su

rface

s & In

terfa

cesP

oly

mer

Syn

thesi

sP

oly

mer

Syn

thesi

s

2D Multiple Quantum MAS NMRImaging of Hyperpolarized GasesDFT CalculationsPulsed and CW EPR Fourier-Transform Rheology

Polymer Chain DynamicsLocal-Order Phenomena

Polyelectrolyte MultilayersSelf Assembled Monolayers

Surface Patterning

PhotoconductorsProtonconductors

Shape-Persistent Macromolecules

Columnar π-π StackingHydrogen-Bonded StructuresCoordination Polymers

Polymerization: Radical, Anionic, Emulsion, Atom-Transfer Radical Isotopic Labelling

SpectroscopyGroup

•••••

•••

•••

••

•••

•

•

Investigation of Structure and Dynamics in Polymeric Systems via Solid State NMR

Introduction •

Solid State NMR •

Polymer dynamics •

Conclusions •

interactions in solid state NMR

resolution enhancement in solid state NMR, magic angle spinning, recoupling methods, double quantum NMR spectroscopy

Polyelectrolyte layers, polybutadiene, PEMA

Pro and Contra of Solid State NMR investigations

Molecular Structures and Dynamics via NMR

i

i0iZ BH I∑γ−=

Important NMR interactions:

Zeemann Interaction :

i

i0iCS BH Iσ∑γ−=Electronic Shielding :

i

i

i)1I2(I2

eQQH IVI∑ −−= hQuadrupol Interaction :

[ ]∑≠

γγπ

μ ⋅−⋅⋅−=ji

jijir3

r4D )r)(r(H 23ji0 IIIIh

Dipol-Dipol Interaction :

∑≠

⋅−=ji

jijiJH IJIIndirect Spin-Spin Interaction :

H = HZ + HQ + HCS + HD + HJ

Interactions in Solid State NMR Spectroscopy

ij0,2ij

2

ji21

r4D )1cos3(H 3ij

ji0 T−θ= ∑≠

γγπ

μ h

PerturbationTheory Orientation dependence of local spin interaction on B0

HQ, HD, HCS, HJ

Isotropic ContributionsHCS: chemical shift

HJ: J-couplings

Liquid state NMR

Anisotropic Contributions

SymmetricHQ: quadrupol

HD: dipol-dipol

HCS: chemical shift

AsymmetricHQ: quadrupol

HCS: chemical shift

Zeemann interaction dominates all other NMR interactions

Distance Orientation

θ

B0B0 θ

1H NMR Spectra in Liquid and in Solid State

60 40 20 0 -20 -40 k-60 Hz

5 0 kHz

20 10 0 kHz

static

30 kHz MAS

Solution

isotropic moleculardynamics

3 kHz4HRMAS soft

matter

rigid solid

dipolarbroadening

Spectral Resolution Enhancement in Solid State NMR

dipol-dipol coupling:

i

j

θij

B0

RF irradiation:

$ ( 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

$,T2 0

0

space spin

0 tC

-x y -y x

tτ ττ τ2τ τ ττ τ2τ τ ττ 2τ

-x y -y x -x y -y

tC

magic angle spinning:

$,R2 0 0 ωR

θ

θm

ωR

θm

ωR

B0 B0 B0 B0

0 tR

t

tR

(CRAMPS)

(Recoupling)HD,eff.

x y -y-x

τ τ

x y -y-x

τ τ

x y-x

τ

Double Quantum NMR Spectroscopy under MAS

ω ωDQ SQ ii

= ∑ ,

I f D tDQ ij ij, ( )= ⋅

d Mdt ≈ 0

preparation reconversionevolution t1 detection t2

6.0 5.0 4.0 3.0 2.0 ppm12

10

8

6

4ppm

CH CH2

-CH2

CH2-CH

CH=CH

doub

le q

uant

umdi

men

sion

(f 1)

single quantum dimension (f2)

properties of double quantum coherences :

Molekulare Stuktur von Silikat-Schichten

Analysis of layered silicates via next nearest neighbor relations

Single quantum dimension

Dou

ble

quan

tum

dim

ensi

on

29Si double quantum spectrum: DQ intensity ∝ r-6 => coordination shells

-150-100-50 ppm0

Q4

Q3

Molecular Structure of Layered Silicates

A

B C

DE

structure of layered silicates from analysis of spatial proximitiesN. Hedin et al., J. Am. Chem. Soc. 126, 9425 (2004).

single quantum dimension

doub

le q

uant

umdi

men

sion

29Si double-quantum spectrum: DQ-Intensities => coordination spheres

Polybenzoxazines

N

O

X

R

N

OH OH

R

n-1X X

Ring Opening

Useful Properties• High Tg

• Good mechanical properties

• Excellent UV and chemical resistance

Unusual Properties• Low water absorption

• Low volumetric expansion on curing

• High modulus

Hydrogen-bonded network

What is the nature of the network?

Benzoxazine Oligomers Studied by 1H DQ NMR

Dimer Trimer Tetramer

Changes in hydrogen bonding structure evident from changing 1H resonances and DQ contacts

Hydrogen Bonds Assigned via DFT-Based Chemical Shift Calculations

1H chemical shifts influenced by proximity to oxygen. Helical structure predicted for polymer.

G. R. Goward et al., J. Am. Chem. Soc. 125, 5792 (2003).

Isolated Dimer Pair - X-ray StructureIntra:Inter = 1:1

Trimer forms Planar Ring Intra:Inter = 2:1

Tetramer forms Overlapping Loop Intra:Inter = 3:1

Calculated and experimental 1H NMR spectra agree, particularly in hydrogen-bonding region.

Dimer Trimer Tetramer

Order Parameter in Liquid Crystalline Phases

2.54 Å

1.83 Å

2.49 Å

2.48 Å

1.83 Å

2.56 Å

A

B

C

CD

F

G

FE

D

chemical structur of nematic model

compound

order parameter Sij :

)1cos3(S 221

ij −θ=

stat,ij

eff,ijij D

DS =

c

A BC

D

E

F

G

G-GF-FE-E

D-E

D-D

C-D

B-CA-C

ppm

8 7 6 5 4 3 2 ppm16

14

12

10

8

6

4

2

doub

le q

uant

um d

imen

sion

single quantum dimension

Order Parameters in Liquid Crystalline Systems

0,0 0,1 0,2 0,3 0,4 0,5 0,60,0

0,1

0,2

0,3

0,4

0,5

BC DQ coherences

DQ

Inte

nsity

[a.

u.]

DQ-Preparation Time [ms]

BC DQ coherence

-100100 0 kHz

orde

r par

amet

erS

0.0

0.1

0.2

0.3

0.4

0.5

0.6

A-C B-C D-D E-E F-F G-G

F

D

C

B

A

CD

E

F

G

orientation of nematic

directorDQ sidebands

DQ intensity

Introduction •

Solid State NMR •

Polymer Dynamics •

Conclusions •

Interaction in solid state NMR

MAS, recoupling, double-quantum NMR

Polyelectrolyte multi layers,reptations-model, scaling laws in polymer dynamics, influence of rigid confinements, conformational stability in PEMA melts.

Pro and Contra Solid State NMR investigations

Investigation of Structure and Dynamics in Polymeric Systems via Solid State NMR

Polyelectrolyte Multi-Layers

Structure of Polyelectrolyte Layers

DQ NMR Investigation of Structure: PEM vs. PEC

N+

SO O

O-

HH

HH

H

H

H

H

H3C CH3

Polyelectrolyte MultilayerPolycationSolution

PolyanionSolution

Anionic Substrate

Aqueous Rinse

After 3 cycles

Polyelectrolyte Complex

PolyanionSolution

Polyelectrolyte Complex Formation

9 8 7 6 5 4 3 2 1

2

4

6

8

10

12

14

16

18

Single Quantum Dimension [ppm]9 8 7 6 5 4 3 2 1

Single Quantum Dimension [ppm]

Double

Quantu

m D

imen

sion [

ppm

]

2

4

6

8

10

12

14

16

18

Double

Quantu

m D

imen

sion [

ppm

]

PolycationSolution

After Drying

Molecular Dynamics in Polyelectrolyte Multi Layers

N+

HH

HH

H 3C CH 3

SO O

O-

H

H

H

H

1 2 3 4 5 6 7 9 108 C

PSS 500 MHzPDADMAC 500MHzPSS 700 MHzPDADMAC 700MHz

200

400

600

800

1000

Number of Layers

T1

[mse

c]

Spin-LatticeRelaxation

10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5

0,01

0,1

1

10

500 MHz700 MHz

correlation time τ [s]

T 1[s

]

theoretical T1 relaxation behavior:

Localization of Water in Polyelectrolyte Multilayers

Layer 1

Layer 2

Layer 3

Layer 4

Layer 5

Layer 6

Layer 7

Layer 8

Layer 9

Layer 10

ppm12 10 8 6 4 2 0

5.0

4.8

4.6

4.4

4.2

4.0

3.8

3.6W

ate

r Che

mi c

al S

hift

[ppm

]

1 2 3 4 5 6 7 8 9 10Layer Number

bulkPDADMAC

bulk PE C

bulk PS S

SO O

O-

H

H

H

H

N+

HH

HH

H3C CH3

8 7 6 5 4 3 ppm

1H MAS NMR Spectra 1H Chemical Shift

M. McCormick et al., Macromolecules 36, 3616 (2003).S. Pawsey et al., J. Am Chem. Soc. 125, 4174 (2003).

Length- and Time Scales in Polymer Dynamics

t > τeslow, collective

Reptation dynamics

t < τe

fast, local dynamics

separation of time scales!

dynamic regimes of the Reptation model :

τR

log(t)

log

[Rn(

t)-R

n(0)

]2

∝ t1/2

∝ t

∝ t1/4

∝ t1/2

τdτe

I. II. III. IV.

DQ Measurements of Dynamics on Different Time Scales

θ(t1)

θ(t0) θm + α(t)

t = 0 t ≈ τe t > τe

I dt dt D d t d tDQt t

t tt

ij eff m m∝ ′ ′′ ⋅ ′ ′′+

+

−∫∫1

12

0

2

22

22

, ,( )

,( )( ) ( )

return-to-origin probability C (t)

corresponds tod t d tm exc m rec t22

22

,( )

. ,( )

.( ) ( )− ′ ⋅ ′′

S Ne≈ −35

1polymer network theory :

Polybutadien : S MMKuhn

e≈ ≈3

5 003.

static systems : Sij(t)=1isotropic motion : Sij(t)=0

S D Dij ij eff ij= , /local order parameter :

Local Order Parameters in 1,4 Polybutadien Melts

SH-H = 0.13

S = 0.06-H2

S = 0.08H2-HT=Tg+50K

⇒ SC=C = 0.20 ± 0.05 6.0 5.0 4.0 3.0 2.0 ppm

12

10

8

6

4ppm

CH CH2

-CH2

CH2-CH

CH=CHdo

ubel

quan

tum

dim

ensi

on(f 1

)

single quantum dimension (f2)

1H double quantum NMR spectrum Dynamic order parameter

via residual dipolar couplings

S

Time Dependence of Local Order Parameter

10-1

100

101

102

103

t / te(T)

~ t -1/2

~ t -1/4

C (t

)tc( ) tc( )

1,0

0,1PB MW ≈ 76 Me

PB MW ≈ 11 Me

PB MW ≈ 4 Me

double-quantum filtered experiments on 1,4 poly-butadien

Reptation-model predicts two scaling laws:

S~t -1/4 and S~t -1/2

R. Graf et al., Phys. Rev. Lett. 80, 5738 (1998).

Molecular Weight Dependent Dynamics of PB Melts in PS-PB

Tethering a PB chain end to a rigid PS block stabilizes the t-1/4-regime

10

0.01

0.1

1

10

PS-b-PB 12k-10kPS-b-PB 22k-24kPS-b-PB 90k-120k

101010.01

0.1

1

10

D CH

=CH

/ kH

z

S(t/

t e)

102 103 104 10510010−1

t/ t e

~t −1/4

Influence of Rigid Confinements on Polymer Dynamics

PS-b-PB PS-b-PB-b-PSPB

0.01

0.1

1

~ t −1/4

t / te

PS-b-PB PB

0.01

0.1

1

10

PS-b-PB-b-PS

S (t/ t

e) CH

=CH

DC

H=C

H /

k Hz

102 103 104 10510010−1 101

~ t −1/2

T. Dollase et al., Macromolecules 34, 298 (2001).

PS-b-PBPB

PB inPS-b-PB

Polymer Dynamics in heterogeneous Polymer Melts

1010.01

0.1

1

10

0.01

0.1

1

10210010−1 103 104 105

t / τe

DC

H=C

H /

kHz

S(t/

τ e) C

H=C

H

PS-b-PB p6 (12k-10k)5 % PB p6 in PS-b-PB d6PB p6 (10k)

~t −1/2

~t −1/4

S(t/

t e)

t / te

Variation of Dynamic Order Along the Polymer Chain

10-2 10-1 100 101 102 10310-3

10-2

chain endchain centerwhole chain

PB(d6)-PB PB(d6)-PB-PB(d6) PB

~ t -1/4

~ t -1/2

t / te

S(t/

t e)

a-PEMA: Isotropisation of Chain Dynamics

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

Gla

ss

Tg

Melt

a-PEMA: Isotropisation of Chain Dynamics

200

150

100200 150 100250

250

[ppm

]ω

2

[ppm]ω1

T = 300 K

ω11

ω22 ω33

180°

CO

13

ω33<10°

ω22

ω11

200

150

100

200 150 100

T = 416 K

tc = 2,1.10-5 s

[ppm

]ω

2

[ppm]ω1

180°C

O13

0° - 180°

T = 394 K

tc = 3,3.10-4 s

200

150

100

200 150 100

[ppm

]ω

2

[ppm]ω1

ωω

180°

CO

13 ω

50°ω

Dynamic Models: Random Jump vs. Rotational Diffusion

rotational diffusion experimental results random jump

200

150

200 150 [ppm]

[ppm]

200

150

200 150 [ppm]

[ppm]

200

150

200 150

tc=3,3 .10-4s

[ppm]

[ppm]tc =3,3.10-4s T = 394 K

200

150

200 150

tc =8,3.10-5s

[ppm]

[ppm]

200

150

200 150 [ppm]

[ppm]

200

150

200 150

tc=8,3.10-5s

[ppm]

[ppm]T = 405 K

M. Wind et al., Solid State NMR 27, 132-139 (2005).

Time Sclaes of Molecular Dynamics PEMA Melts

Arrhenius-diagram of dynamic processes in PEMA

corr

elat

ion

time

[s]

10-8

10-6

10-4

10-2

100

102

2.2 2.4 2.6 2.8 3.0 3.2 3.4

1000 / T [K-1]2.0

Tg = 338K

α-relaxation( tα)

β-relaxation( tβ)

αβ-relaxation( tαβ)

NMR

DielectricPCS

conformationalisotropisation (tR/I)

Length Scale of Isotropisation Process

**

*

*

**

*

*

T - Tg

95 K

55 K

410 K

449 K

395 K

434 K

387 K

426 K

322 K

346 K

379 K

403 K

300 K 300 K 300 K 221 K278 K

δ [ppm]100150200250

δ [ppm]100150200250

δ [ppm]100150200250

δ [ppm]100150200250

δ [ppm]100150200250

Mw = 600 kg mol -1 Mw = 15,9 kg mol -1 Mw = 7,6 kg mol -1 Mw = 1,4 kg mol -1 Mw = 0,46 kg mol -1

Mw/Mn = 1,53 Mw/Mn = 1,61 Mw/Mn = 1,48 Mw/Mn = 1,07 Mw/Mn = 1,14

from radicalic polymerisation from anionic polymerisation

M. Wind et al., Macromol. Chem. Phys. 206, 142 (2005).

Organisation in Poly(Methacrylats): WAXS(LVDW)

PMMA

PEMA

PBMA

PHMA

Inte

nsity

[a.u

.]

q [nm-1]0 10 20

II/I

WAXS-DataIII

(VDW)

III

?

0

0.4

0.8

1.2

1.6

0 2 4 6 8 10 12number of side chain C atoms

Bra

ggdi

stan

ce d

[nm

]

I

II

III

(VDW)

(LVDW)

Bragg distances

syndiotacticpoly(methacrylate)

main chain

side chains

dI

dIII

d0

dIII

dII

"Nano Layers"

isotacticPEMA

main chains

side chains

extrapolatedlokal structur:

M. Wind et al., J. Chem. Phys. 122, 14906 (2005).

Introduction •

Solid State NMR •

Polymer Dynamics •

Conclusions •

Interaction in solid state NMR

MAS, recoupling, double-quantum NMR

polyelectrolyte layers, polybutadiene, PEMA

solid state NMR investigations

Investigation of Structure and Dynamics in Polymeric Systems via Solid State NMR

+

Pro and Contra of Solid State NMR Investigation

T = 394 K

tc = 3,3.10-4 s

200

150

100

200 150 100

[ppm

]ω

2

[ppm]ω1

ωω

T = 394 K

tc = 3,3.10-4 s

200

150

100

200 150 100

[ppm

]ω

2

[ppm]ω1

ωω

θ(t1)

θ(t0) θm + α(t)

elucidation local structures in partially disordered systems

supra-molecular structures in hydrogen bonded systems

local molecular dynamics

needs expertise-expensive-

correlation of dynamic processes and chemical structure

single quantum dimension

doub

le q

uant

umdi

men

sion

single quantum dimension

doub

le q

uant

umdi

men

sion

- ...

+

+

+

Acknowledgements

Prof. Dr. H. W. Spiess ($, €, …)

Dr. I. Schnell, Dr. K. Saalwächter, Dr. M. Feike,Dr. S. Hafner, Prof. D. Demco. (NMR)

Prof. B. Chmelka, Dr. N. Hedin (layered silicates)

Prof. K. Ishida, Dr. D. Sebastiani (polybenzoxazines)

Prof. L. Reven, Dr. M. McCormick (polyelectrolytes)

Prof. A. Heuer (polymer theory, …)

Dr. T. Dollase, Dr. M. Neidhöfer (polybutadiene)

Dr. M. Wind, Dr. W. Steffen, Prof. Do Yoon (PEMA)