ISSP/Soft
Aug. 9-12, 2010�

Rheo-SANS Studies on Structure Evolution
in Clay-Poly(ethylene oxide) MixedSolutions- shear thickening -�Mitsuhiro Shibayama,
M. Takeda, T. Matsunaga, T. Nishida,
H. Endo, and T. Takahashi1)�
Neutron Science Lab.,
Institute for Solid State Physics (ISSP),
University of Tokyo,
Kashiwa, 277-8581, Japan,1) Nagaoka University of Technology,

Nagaoka, Niigata 940-2188, Japan �Neutron Science Lab., ISSP
JRR-3M, JAEA
(20MW reactor)

JAEA
ISSP
Tokyo

100km

Guest house(~1994)�

MLF�
ISSP,U. Tokyo

JRR3�

U. Tokyo
ISSP: Ins,tute for Solid State Physics
JAEA: Japan Atomic Energy Agency

J-PARC�

JAEA, Tokai�University-owned Instruments at JRR-3
Reflectivity

TOF

High resolution

Small angle
Triple-axis
Reactorhall

Guide hall
Diffraction
Triple-axis

University-owned instruments: 14, ISSP 9, Tohoku U. 3, Kyoto U. 2
No. proposals: ~300
No. users (man.day)：in-house 2000, outside 5000, total 7000
No. papers：~100 /y3

Rheo-SANS
SANS-U, ISSP, Univ. Tokyo
Wavelength: 7 Å
SDD: 2, 4, 8 m, 12 m
Q range: 0.002 - 0.1 Å-1Okabe et al., J. Appl. Cryst., 2005, 38, 1035.

SANS-UMCR 501 (Anton Paar)

MCR 501 (Anton Paar)
Torque : 0.1 µNm - 230 mN mTorque resolution : 0.001 µN m
Quartz cellCylinder
Diameter : 48 mm
Angle : 2.2 ˚BeakerDiameter : 50 mm
Gap size : 1 mm
Sample amount: 10 ml

Tangential

RadialShake gels
Silica-PA

Laponite (clay)-PEO
liquidShake gelthickening

Silica suspensions inpolyacrylamide solutions
Y. Otsubo, K. Umeya
J.Rheology, 1984, 28, 95-108.
Shear-induced gelation of laponite-PEO mixtures
J. Zebrowski, D. A. Weitz et al.
Colloid Surface and Interface, 213, 2003, 189.

Rheo-SANS of Shear thickening�
NE/HEC
Nanoemulsion/polymer�clay/PEO
Clay/polymer�

CTAB/NapTS
micelle0 s‐1�

γ = 100 s-1�radialtangential�

100 s‐1�
radialtangential�

SDD = 8 m�SDD = 1 m�Shibayama et al.,
JCP, 2007, 127, 144507.�

Takeda et al.,Macromolecules, in press.�

Percolation transition�

Takeda et al.,In preparation (Poster P113)�

Part I: NE/HEC Shake gel�

sampleShake gels, composed of a mixed solution of polymer and nano-size
emulsion, show both shear thinning and shear thickening behaviors.

Nano-emulsion was made byhigh pressure extrusion of 30 wt % glycerol,
3 wt % ethanol, 16 wt % oil.

HEC
Nano-size emulsion

Nano-particles in the emulsion becomecross-linkers to which polymer chains areattached.

Polymer : 2-hydroxyethyl cellulose (HEC) : Mv = 1.30 x 106 g/mol
Particle : nano-size emulsion (NE) : (Diameter ≈ 30 nm)
Concentrations: polymer = 0.4 %, emulsion = 12 %J. Chem. Phys, 2007, 127, 144507

CNE and CHEC dependence of dilatancy
Samples(polymer)

Sample code: D50/04SK-1 50%

HEC 0.4%

Stock solution : ≈ 25%

Dilatancy factor

F�Def.
Dilatancy Factor= viscosity ratio
after and before
Shaking

A tuning-fork vibration
Viscometer(CJV5000, A&D Co. Ltd.,Japan)@ 25°C, 30 Hz

Flow behavior: shear-induced transition
D50/04�

4104

10

D50/04 η ascent
D50/04 η descent
D50/04 σ ascent
D50/04 σ descent
0.4wt% HEC
50wt% NE
0.4wt% HEC + 50wt% NE

310310210η

110110η(HEC+NE)
0viscosity

σ (Pa)

η (Pa • s)

210100

Shear stressdση≡dγ˙-110σ(A)-110(B)(C)(D)10ηHEC + ηNE

ηHEC-2ηNE10-410-310-210-210Shear rate

-1.

0

110 -1 10γ (s )210310€ 410
10Viscoelastic transition
310

G' > G"
2G', G" / Pa • s

10G'(ω) ∼ ω0gel

after
1

1001270 times

G"(ω) ∼ ω0.71

10Storage, and 10-1
Loss moduli-2G"(ω) ∼ ω0

beforesolutionG'(ω) ∼ ω0.91

γ = 5%
at 25 ˚C

G' < G"

100101ω (rad/s)

10G’(ω) and G”(ω) were measured before and after shearing(dγ/dt = 100 s-1 for 10 min)

2D SANS Patterns of Shake Gel
010S(q)

310-1

102-1

1-2P(q)

10NE 50 wt%
HEC 0.4 wt%
P(q)
S(q)

1010010-3-4-1

10-2

10-3

1010-5

10

No anisotropic patterns

10P(q), S(q)Intensity (cm )10-6-101010-1q (nm )The shape of the NE and the inter-particle distance are preserved and only
the long-range inhomogeneities increase by shearing.

Discussion 1: Intuitive interpretation
410D50/04 η ascent
D50/04 η descent
D50/04 σ ascent
D50/04 σ descent
0.4wt% HEC
50wt% NE
0.4wt% HEC + 50wt% NE

41031031010η

1101

10010

σ-1(A)

10σ (Pa)η (Pa • s)

2

10

2

010(B)

(C)

(D)

-1

10-2

10-2

10-4-31010-210-1100.
γ (s-1)

101

210

3

1010

4

10Ascent
�(A) Newtonian
�(B) Shear thinning
�(C) Shear thickening
�(D) Slipping
Descent and 2 nd run
�Dilatant behavior !!
�Once a high shear is applied,
the structure is formed and the relaxation
time becomes very long.

Percolation transition
Shear

From SANS, we know a does not change with shear.

Flow direction

Discussion 2: Estimation of shear
stress at the transition
Entropy elasticity of a single Gaussian chain

σ=RR
f
3kT
==E
1/ 2
A A R02 1/ 2 R02 1/ 2
R02

Approx.1: A ≈ a2σ≈€
G = E /3,

€R / R02

1/ 2

Cross section ARf
3kT=a 2 a 2 R02 1/ 2 R02 1/ 2→γ

RkTkTσ = Gγ =€=γ22 1/ 22 1/ 222 1/ 2a R0
R0a R0Approx.2: γ ≈ 1€€kT
σ tr = Gγ ≈ 3aσtr = 45.7 [J/m2 = Pa]

Predicted by
SANS data only

σtr = 37.3 [J/m2 = Pa]

Rheology

Summary 1: NE/HEC mixture
Summary
・Shear-induced gelation in a mixture of NE and HEC wasinvestigated by Rheo-SANS.
・ The mixture exhibits a distinct viscosity-jump (dilatancy) at
the shear rate of 4 s-1, which corresponds to a steep upturnof SANS intensity at the low q-region.
・No anisotropy was observed even at the shear rate of 100 s-1.
・After scission of shearing, a slow relaxation was observedof the order of days in both SANS intensity and viscosity.
Conclusion(1) The dilatancy effect becomes largest when a ≈ Rh.
(2) The shear stress at the transition can be simply estimatedonly with the structure parameters.
(3) The dilatancy behavior is due not to non-Gaussian chains, but topercolation transition of the system.
J. Chem. Phys, 2007, 127, 144507.

Part II: Shear thickening of 
Clay/PEO�Sampleshake gel composed of clay-PEO mixture•Laponite (XLG) (clay platelet)
10 Å300 Å•poly(ethylene oxide) (PEO)
Mw = 400,000--CH-[]-n2CH2O-•water H2O and D2O mixtures for SANS�Comparison: Clay-PEO
2% clay

Radial0 s-1

100 s-1

0 s-1

Tangential

100 s-1

parallel

3% PEO (1.0 x 106 g/mol)

2% Clay + 3% PEO

FlowperpendicularClay Orientation in a flow field
Schematic illustration showing the relationship between the anisotropyof scattering intensity and clay’s orientation.

Rheo-SANS of clay/PEO�

Schmidt et al., Macromolecules, 2005�

Rheological behaviors
shear thickening system�

shear thinning system�
Mw = 1,000 kg/mol
C3P2PEOFclay

Mw = 400 kg/mol

F = ηaft / ηbef

C3P20�

Matsunaga et al.,Macromolecules, 2010, 43, 5075.�

Sample code:C2P04；clay:2 wt%-PEO:0.4 wt%
Phase diagram of shear thickening behavior
with contour lines of F.
3.0%�

Aging of clay 2 wt%�viscosity�.�η (γ→0)Gelation at stationary stateDLS�

solution；g(2)(0) = 1
Gel point；power law with τ��→ self-similar cluster formation
gel；suppression of g(2)(0)����→ gel mode, nonergodicity

Evolution of clay-PEO mixture�
viscosity�

DLS�

.�
1. η (γ→0) increase.�
2. Lowering of γ at shear thickening
3. Gelation at stationary state
Origin of structural evolution⇒ gelation of card-house structure of clay�Rheology and SANS measurements�
C2P08 φD2O =1 tage = 3 day�
SDD = 8 m, 4m.�

γ = 0 s-1�The scattering pattern changed to anisotropic at 500 s-1.

.�To investigate γ = 0, 100, 500 s-1 more precisely, CV-SANS was applied.

C2P08�

Scattering from three-component systems
22I(q) ≈ Δρ C SCC (q) + 2Δρ CΔρ P SCP (q) + Δρ P SPP (q)Self-term�SCC(q)�

SPP(q)�

€PEO only�Clay only�
Cross-term�

I(q)�
SCP(q)�
Interaction of clay and PEO�Contrast Variation SANSΔρCΔρP

ρCclay�ρsolventWρPPEO�

SCC�

φD2O=�

singular value
decomposition�

I(q) measurements�

…�

I(q)�

SCP�

SPP�

Partial scatt. fun.�2D scattering Functions for C2P08

Col/SDD=8 m/8 m.
γ = 0 s-1

100 s-1 500 s-1

SCC�

SCP�

SPP�
Flow direction

Conclusion 2: Clay/PEO
・Structural analyses were conducted on a clay/PEO mixture C2P08
undergoing shear thickening.
・Orientation of clay and polymer chains in C2P08 with shear thickening
was observed by means of Rheo-SANS and Rheo-BF.
・CV-Rheo-SANS result revealed the origin of orientation at shear thickening
threshold.
・Both of clay and PEO were orientated parallel to the flow direction.
・CV-Rheo-SANS data gave not only the information of orientation but alsothat of clay-PEO interaction.
・PEO chains adsorbed on clay surfaces are peeled off with shear thickening andbridge clay platelets, resulted in percolation transition.
Mechanism of shear thickening

stationary

Shear thinning

Shear thickening

Macromolecules, in press.�

Viscosity and 2D scattering patternon 5 mM_0.7�

10 s-1� 20 s-1� 50 s-1�1 s-1�

100 s-1� 500 s-1�Takeda et al., Poster P113�

29�

Acknowledgement�

M. Takeda�

H. Endo�T. Matsunaga�

Ministry of Education, Science, Sports and Culture, Japan(Grant-in-Aid for Scientific Research (A), 2006-2008, No. 18205025,
and for Scientific Research on Priority Areas, 2006-2010, No. 18068004)
SANS experiment: NSPAC, ISSP, Atomic Energy Initiative, MEXT, 2008-2010�