1. 0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
1% Ultrathix™ P-100 1% Stabileze® QM 1% Carbopol® 980
Sensoryevaluationrating
Slipperiness/Lubricity
Cushion
Initial spreadibility
Rub-out spreadibility
1%UltrathixTM P100
1%Stabileze® QM
1%Carbopol® 980
Cushion
Initial Spreadability
Rub-out
Spreadability
Slipperiness
Pick-up
-2
0
2
-6 -4 -2 0 2 4 6
F2(19.00%)
F1 (81.00 %)
Biplot (axes F1 and F2: 100.00 %)
1% Ultrathix™ P-
100
1% Stabileze® QM
1% Carbopol® 980
-4
-3
-2
-1
0
1
2
3
4
-6 -5 -4 -3 -2 -1 0 1 2 3 4 5
F2(23.99%)
F1 (76.01 %)
Observations (axes F1 and F2: 100.00 %)
Cushion
Initial Spreadability
Rub-out Spreadability
Slipperiness
Pick-up
ESS (w=1rps)G' S (w=1rps)
ESS (w=10rps)
G' S (w=10rps)
ESS (w=20rps)
G' S (w=20rps)
ESR (w=1rps)
G' R (w=1rps)
SV @ 10s-1
SV @ 100s-1
SV @ 500s-1
MNF
T0
m
n
beta
s
-1
-0.75
-0.5
-0.25
0
0.25
0.5
0.75
1
-2 -1.75 -1.5 -1.25 -1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2
F2(23.99%)
F1 (76.01 %)
Variables (axes F1 and F2: 100.00 %)
Cushion
Initial Spreadability
Rub-out Spreadability
Slipperiness
Pick-up
G' CR4
G'L/G'M CR4
e3CR4
tand CR4
eta'L/eta'M CR4
v3 CR4
G' CS4
G'L/G'M CS4
e3CS4
tand CS4
eta'L/eta'M CS4
v3 CS4
G' CR2
G'L/G'M CR2
e3CR2
tand CR2
eta'L/eta'M CR2
v3 CR2
G' CS2
G'L/G'M CS2
e3CS2
tand CS2
eta'L/eta'M CS2
v3 CS2
G' CS001
G'L/G'M CS001
e3CS001
tand CS001
eta'L/eta'M CS001
v3 CS001
-1
-0.75
-0.5
-0.25
0
0.25
0.5
0.75
1
-1.25 -1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1 1.25
F2(34.28%)
F1 (65.72 %)
1% Ultrathix™ P-100
1% Stabileze® QM
1% Carbopol® 980
-6
-4
-2
0
2
4
-8 -6 -4 -2 0 2 4 6 8
F2(34.28%)
F1 (65.72 %)
0.1
1
10
100
1000
10000
0.01 0.1 1 10 100
ShearStress(dyn/cm2),Shearviscosity(P)
Time, s
shear stress
shear viscosity
t=0 sec,
shear
rate=0.5 s-1
t=5 sec,
shearrate=0.5 s-1
1
10
100
1000
10000
0.01 0.1 1 10 100
ShearStress(dyn/cm2),Shearviscosity(P)
Time, s
shear stress
shear viscosity
t=0 sec,
shear
rate=0.5 s-1
t=5 sec,
shearrate=0.5 s-1
1
10
100
1000
10000
0.01 0.1 1 10 100
ShearStress(dyn/cm2),Shearviscosity(P)
Time, s
shear stress
shear viscosity
t=0 sec,
shear
rate=0.5 s-1
t=5 sec,
shearrate=0.5 s-1
(a) (b) (c)
Characterization of yield stress and slip behavior of skin/hair care gels using steady flow and LAOS
measurements and their correlation with sensorial attributes
Seher Ozkan and Tim W. Gillece
Material Science Group, Global R&D, International Specialty Products, NJ
…ABSTRACT …LAOS ANALYSIS
…WALL SLIP EFFECT ON DYNAMIC AND STEADY MEASUREMENTS
…References
1. Steven P. Meeker, Roger T. Bonnecaze, Michel Cloitre. “Slip and flow in pastes of soft particles: Direct observation and Rheology.” J. Rheol. (2004) 48(6): 1295-1320
2. D. M. Kalyon. “Apparent slip and viscoplasticity of concentrated suspensions.” J. Rheol. (2005) 49(3): 621-640
3. Randy H. Ewoldt, A. E. Hosoi and Gareth H. McKinley. “New measures for characterizing nonlinear viscoelasticity in large amplitude oscillatory shear.” J. Rheol.
(2008) 52(6): 1427-1458
4. Morten Meilgaard, Gail Vance Civille, B. Thomas Carr. Sensory Evaluation Techniques. CRC Press, 3rd edition, 1999.
Gels made with three different polymers widely used as rheology modifiers in cosmetic formulations (Crosslinked
poly(acrylic acid (Carbopol® 980), crosslinked methyl vinyl ether/maleic anhydride copolymer (Stabileze® QM) and
crosslinked vinyl pyrrolidone/acrylic acid copolymer (UltrathixTM P100)) were characterized by rheological and sensory evaluation
methods to determine the relationship between sensorial perception and rheological parameters.
Both conventional rheological characterization methods and a more recent method, Fourier Transform Rheology with Large
Amplitude Oscillatory Flow data (LAOS), were utilized to characterize the material with and without wall slip. Sensorial analyses were
implemented in-vivo to evaluate the perceived ease of initial and rub-out spreadability, cushion, pick-up, and slipperiness attributes of
the gels.
Results were statistically analyzed by analysis of variance (ANOVA), principle component analysis (PCA) and linear regression
analysis. Sensory characteristics discriminated the three materials and PCA and linear regression analyses revealed that sensory
attributes could be well predicted by rheological methods.
…MOTIVATION AND CHALLENGES
Sensory properties of personal care products contribute substantially to the overall consumer acceptance.
Different sensory evaluation techniques are applied to help the formulator to identify and define the
sensory profile of a product but they are costly and time consuming.
Rheological methods can be employed to mimic the sensory perception experienced by consumer and
subjective descriptions sensory attributes can be correlated quantitative instrumental measurements of
rheological parameters.
…Conclusions
 Rheological methods can be successfully applied to objectively and quantitatively describe sensory attributes of cosmetic products.
 The occurrence of wall-slip may contribute to the sensory perception of the hydrogel based personal care products and should be characterized.
 Applied shear rate range may contribute to the material’s response to given deformation and sensory perception of the product.
 Using Fourier transform analysis in large amplitude oscillatory shear flow can be an effective method to correlate sensory rating results in skin/hair
gels. Results indicate that surface roughness and being in linear, transition and non-linear region determines which LAOS analysis parameters would
correlate with which sensory parameters. Wall slip has to be taken into account when correlating LAOS analysis parameters.
Rheological characterization of hydrogels and gel-like percolated suspensions/emulsions and determination of yield stress present
special challenges associated with thixotropy, viscoplasticity and wall slip, which renders the application of generally accepted
rheological characterization methodologies difficult.
Figure 2. Strain amplitude dependency of elastic stress (G’ x g (dyn/cm2)) at 1 Hz frequency measured by
smooth surface fixtures (a) and rough surface fixtures (b).
Figure1. Strain amplitude dependency of storage modulus (G’(dyn/cm2)) at 1 Hz frequency measured by
smooth surface fixtures (a) and rough surface fixtures (b).
Figure 3. Shear stress and shear viscosity versus time measured by steady torsional experiment using 25mm parallel plate fixtures at 0.5 s-1 shear rate and 1mm gap opening for 1% Carbopol® 980 (a), 1%Stabileze® QM
(b) and 1% UltrathixTM P100 (c). Insets show the onset of slip at the material/plate interface.
100
1000
10000
100000
0.01 1 100
G'(dyn/cm2)
Strain, %
1%Ultrathix P100,w=1rps
1% Stabileze QM, w=1rps
1% Carbopol980, w=1rps
100
1000
10000
100000
0.01 1 100 10000
G'(dyn/cm2)
Strain, %
1%Ultrathix P100,w=1rps
1% Stabileze QM, w=1rps
1% Carbopol980, w=1rps
(a) (b)
100
1000
10000
0.01 0.1 1 10 100 1000
ElasticStress(dyn/cm2)
Strain, %
1%Ultrathix P100,w=1rps
1% Stabileze QM, w=1rps
1% Carbopol980, w=1rps
100
1000
10000
0.01 0.1 1 10 100 1000 10000
ElasticStress(dyn/cm2)
Strain, %
1%Ultrathix P100,w=1rps
1% Stabileze QM, w=1rps
1% Carbopol980, w=1rps
(a) (b)
1% Ultrathix™ P-100 1% Stabileze
®
QM 1% Carbopol
®
980
Maximum elastic
stress, Pa (w=1 Hz),
smooth surface
29 139 136
Maximum elastic
stress, Pa (w=10 Hz),
smooth surface
159 206 209
Maximum elastic
stress, Pa (w=20 Hz),
smooth surface
191 246 259
Maximum elastic
stress, Pa (w=1 Hz),
rough surface
169 175 164
Figure 4. Shear stress versus shear rate data measured by steady torsional experiment using 20mm smooth surface
parallel plate fixtures at 1mm and 1.5mm gap opening for 1% Carbopol® 980 (a) and 1% Stabileze® QM (b). Solid line
represents the Herschel-Bulkley fit of slip corrected data.
1
10
100
1000
0.00001 0.001 0.1 10 1000
ShearStress,Pa
Shear Rate s-1
Steady torsionaldata, gap=1.5mm
Steady torsionaldata, gap=1mm
Herschel-Bulkleyfit
Slipcorrectedexperimental data
1
10
100
1000
0.00001 0.001 0.1 10 1000
ShearStress,Pa
Shear Rate s-1
Steady torsionaldata, gap=1.5mm
Steady torsionaldata, gap=1mm
Herschel-Bulkleyfit
Slipcorrectedexperimental data
(a) (b)
1% Ultrathix™ P-100 1% Stabileze
®
QM 1% Carbopol
®
980

0, Pa
161.5 168.5 123.7
m, Pa.s1/n
12 22.8 41.5
n 0.54 0.52 0.43

m.(Pa.s1/nb
)nb
0.0033 0.141 0.024
sb 1.07 0.35 0.43
Table III. Herschel-Bulkley model parameters and Navier’s slip coefficients for 1% gels.
Table I. Yield stress values determined from maximum elastic
stress calculations for 1% gel samples at different frequency and
surface conditions.
1% Ultrathix™ P-100 1% Stabileze
®
QM 1% Carbopol
®
980
G’, Pa (w=1 Hz),
smooth surface 859 788 565
G’, Pa (w=10 Hz),
smooth surface 932 830 626
G’, Pa (w=20 Hz),
smooth surface 923 884 641
G’, Pa (w=1 Hz),
rough surface 851 765 550
Table II. Storage modulus, G’, values in the linear viscoelactic region for
1% gel samples at different frequency and surface conditions.
…Acknowledgement
We thank Dr. Gareth H. McKinley and Dr. Randy H. Ewoldt for their guidance regarding LAOS analysis and making MITlaos software available for us.
…CORRELATION OF SENSORY RATINGS WITH CONVENTIONAL AND LAOS
RHEOLOGICAL PARAMETERS
Figure 8. Sensory and LAOS analysis data together:
Principle component analysis.
Figure 7. Sensory and rheological parameter data together:
Principle component analysis.
Principle component analysis shows that cushion, slipperiness and
pick-up are related while initial and rub out spreadability are related
but are in contrast with cushion, slipperiness and pick-up.
Figure 6. Sensory data: Principle component analysis.
y = -163.84x + 1474.6
R² = 0.9822
y = -167.81x + 1551.1
R² = 0.9988
y = -159.97x + 1535.9
R² = 0.9437
y = -166.45x + 1471
R² = 0.9926
0
100
200
300
400
500
600
700
800
900
1000
0.00 2.00 4.00 6.00
G',Pa
Cushion Rating
w=1rps with slip
w=10rps with slip
w=20rps with slip
w=1, no slip
y = 60.561x - 181.02
R² = 0.9789
0
20
40
60
80
100
120
140
160
0.00 2.00 4.00 6.00
NormalForceDuring
Tesnsion,g
Cushion Rating
y = 16.107x - 47.044
R² = 1
0
5
10
15
20
25
30
35
40
45
0.00 2.00 4.00 6.00
Consistencyindex,Pa.s1/n
Cushion Rating
y = -0.0637x + 0.7826
R² = 0.9512
0
0.1
0.2
0.3
0.4
0.5
0.6
0.00 2.00 4.00 6.00
PowerLawindex
Cushion Rating
Figure 9. Linear regression fit results of Cushion ratings with G’ measured in
linear viscoelastic region, normal force, power low index (n) and consistency index
(m) of Herschel-Bulkley fit.
y = 5.1178x + 15.329
R² = 0.9932
0
5
10
15
20
25
30
35
40
45
50
0.00 2.00 4.00 6.00
G',Pa
Cushion Rating
Rough surface, 400% strain
y = 6.2687x + 6.7486
R² = 0.9971
0
5
10
15
20
25
30
35
40
45
0.00 2.00 4.00 6.00
G',Pa
Cushion Rating
Smooth surface, 400% strain
y = -169.01x + 1453
R² = 0.9924
0
100
200
300
400
500
600
700
800
900
0.00 2.00 4.00 6.00
G',Pa
Cushion Rating
Smooth surface, 1% strain
y = -0.3106x + 2.9379
R² = 1
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0.00 2.00 4.00 6.00
tand
Cushion Rating
Smooth surface, 200% strain
y = 3.6219x + 15.4
R² = 0.9895
0
5
10
15
20
25
30
35
40
45
0 2 4 6 8
G',Pa
Pick-Up Rating
Smooth surface, 400% strain
y = 0.9344x - 9.1534
R² = 0.9967
-6
-5
-4
-3
-2
-1
0
0 2 4 6 8
v3,Pa.s
Pick-Up Rating
Smooth surface, 400% strain
y = -0.1781x + 2.5019
R² = 0.9774
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 2 4 6 8
tand
Pick-Up Rating
Smooth surface, 200% strain
y = -98.159x + 1222.5
R² = 0.9952
0
100
200
300
400
500
600
700
800
900
0 2 4 6 8
G',Pa
Pick-Up Rating
Smooth surface, 1% strain
y = 0.0814x + 0.926
R² = 0.9833
1.28
1.3
1.32
1.34
1.36
1.38
1.4
1.42
1.44
0.00 2.00 4.00 6.00 8.00
EtaL/EtaM
Initial Spreadability Rating
Rough surface, 200% strain
y = -0.0215x + 1.0434
R² = 0.9552
0.905
0.91
0.915
0.92
0.925
0.93
0.935
0.94
0.945
0.00 2.00 4.00 6.00 8.00
G'L/G'M
Initial Spreadability Rating
Smooth surface, 1% strain
y = 1.2779x - 4.5112
R² = 0.9236
0
0.5
1
1.5
2
2.5
3
3.5
4
0.00 2.00 4.00 6.00 8.00
v3,Pa.s
Initial Spreadability Rating
Smooth surface, 1% strain
y = -0.21x + 2.255
R² = 0.9423
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0.00 2.00 4.00 6.00 8.00
EtaL/EtaM
Initial Spreadability Rating
Smooth surface, 200% strain
y = 0.0364x + 0.9388
R² = 0.9619
1.09
1.095
1.1
1.105
1.11
1.115
1.12
1.125
1.13
1.135
1.14
1.145
0.00 2.00 4.00 6.00
EtaL/EtaM
Rub-Out Spreadability Rating
Rough surface, 400% strain
y = -0.0268x + 1.063
R² = 0.8176
0.905
0.91
0.915
0.92
0.925
0.93
0.935
0.94
0.945
0.95
0.00 2.00 4.00 6.00
G'L/G'M
Rub-Out Spreadability Rating
Smooth surface, 1% strain
Figure 10. Linear regression fit results of sensory ratings
and various LAOS analysis parameters.
Strain
amplitude, %
G’, Pa G’L/G’M e3, Pa tand hL/hM v3, Pa.s Physical meaning
1% Ultrathix™ P-100 400 34.38 3.74 11.45 2.11 1.14 -2.56 Shear thinning, Strain stiffening
1% Stabileze® QM 400 37.06 4.08 12.57 2.35 1.10 -3.15 Shear thinning, Strain stiffening
1% Carbopol® 980 400 43.64 1.79 8.48 1.65 1.12 -1.61 Shear thinning, Strain stiffening
1% Ultrathix™ P-100 200 89.22 1.78 15.16 1.32 1.43 3.06 Shear thickening, Strain stiffening
1% Stabileze® QM 200 86.96 2.07 14.79 1.44 1.31 2.63 Shear thickening, Strain stiffening
1% Carbopol® 980 200 90.01 1.28 8.29 1.05 1.32 3.32 Shear thickening, Strain stiffening
Table IV. Chebyshev coefficients, which are calculated from large amplitude oscillatory flow (LAOS) data using MITlaos software,
of 1% gels. Experiments were conducted 1 Hz frequency using rough surface fixtures at 200% and 400% strain amplitudes.
Strain
amplitude, %
G’, Pa G’L/G’M e3, Pa tand hL/hM v3, Pa.s Physical meaning
1% Ultrathix™ P-100 400 29.51 3.79 10.38 2.68 0.83 -5.55 Shear thinning, Strain stiffening
1% Stabileze® QM 400 34.27 4.46 12.48 2.59 1.03 -4.21 Shear thinning, Strain stiffening
1% Carbopol® 980 400 41.10 1.86 8.48 1.80 1.04 -2.56 Shear thinning, Strain stiffening
1% Ultrathix™ P-100 200 65.78 1.79 11.7 1.8 0.95 -2.82 Shear thinning, Strain stiffening
1% Stabileze® QM 200 81.00 1.93 14.87 1.59 1.24 1.25 Shear thickening, Strain stiffening
1% Carbopol® 980 200 84.50 1.40 9.54 1.23 1.25 1.70 Shear thickening, Strain stiffening
1% Ultrathix™ P-100 1 843.2 0.91 -4.5 0.07 2.07 3.44 Shear thickening, Strain softening
1% Stabileze® QM 1 704.97 0.94 -1.79 0.08 1.89 1.70 Shear thickening, Strain softening
1% Carbopol® 980 1 529.09 0.94 -1.58 0.08 1.87 1.56 Shear thickening, Strain softening
Table III. Chebyshev coefficients, which are calculated from large amplitude oscillatory flow (LAOS) data using MITlaos software,
of 1% gels. Experiments were conducted 1 Hz frequency using smooth surface fixtures at 1%, 200% and 400% strain amplitudes.
Fourier transform analysis on the large amplitude oscillatory data collected with rough and smooth surfaces at 1, 200 and 400% strain
amplitude values. Sinusoidal stress response signal collected from the sample was decomposed into elastic and viscous stress
contributions using symmetry arguments following the methods given by Cho et al. (2005) and Ewoldt et al (2008). Chebyshev
polynomials (closely related to the Fourier decomposition) were calculated using MITlaos software (Ewoldt et al (2008))
-500.0 -400.0 -300.0 -200.0 -100.0 0.0 100.0 200.0 300.0 400.0 500.0
-4000.0
-3000.0
-2000.0
-1000.0
0.0
1000.0
2000.0
3000.0
4000.0
Strain(t) [%]
stress(t)()
[dyn/cm²]
stress(t)
1%UltrathixP100, w=1rps, 400% Strain
1%StabilezeQM, w=1rps, 400% Strain
1%Carbopol980, w=1rps, 400% Strain
-500.0 -400.0 -300.0 -200.0 -100.0 0.0 100.0 200.0 300.0 400.0 500.0
-4000.0
-3000.0
-2000.0
-1000.0
0.0
1000.0
2000.0
3000.0
4000.0
Strain(t) [%]
stress(t)()
[dyn/cm²]
stress(t)
1%Carbopol980, w=1rps, 400% Strain, smooth surface
1%UltrathixP100, w=1rps, 400% Strain, smooth surface
1%StabilezeQM, w=1rps, 400% Strain, smooth surface
Figure5. Comparison of Lissajous representation of the measured stress response
upon a sinusoidal strain input for 1% gels of UltrathixP100, StabilezeQM and
Carbopol980 (pH adjusted to 7). 400% strain amplitude and 1rps frequency.