Tough hydrogels can be synthesized by incorporating self-healing physical crosslinks in a chemically crosslinked gel network. Due to the breaking and reattachment of these physical crosslinks, these gels exhibit a rate-dependent behavior that can be different from a classical linear viscoelastic solid. In this work, we develop a theory to describe the linear mechanical response of a dual-crosslink gel in a parallel-plate torsional rheometer. Our theory is based on a newly developed finite strain constitutive model. We show that some of the parameters in the constitutive model can be determined by carrying oscillatory torsional experiments. For consistency, we also show that the torsion data in an oscillatory test can be predicted using our theory with parameters obtained from tension tests. Our theory provides a basis for interpreting and understanding the test data of these gels obtained from rheometry.

1.
Bird
,
R. B.
,
R. C.
Armstrong
, and
O.
Hassager
,
Dynamics of Polymeric Liquids: Fluid Mechanics
, 2nd ed. (
Wiley
,
New York
,
1987
), Vol. 1.
2.
Bower
,
A. F.
,
Applied Mechanics of Solids
(
CRC, Taylor and Francis Group
, London,
2010
).
3.
Calvert
,
P.
, “
Hydrogels for soft machines
,”
Adv. Mater.
21
(
7
),
743
756
(
2009
).
5.
Ferry
,
J. D.
,
Viscoelastic Properties of Polymers
(
John Wiley & Sons
, New York,
1980
).
6.
Gong
,
J. P.
, “
Why are double network hydrogels so tough?
,”
Soft Matter
6
(
12
),
2583
2590
(
2010
).
7.
Gong
,
J. P.
,
Y.
Katsuyama
,
T.
Kurokawa
, and
Y.
Osada
, “
Double-network hydrogels with extremely high mechanical strength
,”
Adv. Mater.
15
(
14
),
1155
1158
(
2003
).
8.
Green
,
A. E.
, and
W.
Zerna
,
Theoretical Elasticity
(
Oxford University
,
London
,
1968
).
9.
Green
,
M. S.
, and
A. V.
Tobolsky
, “
A new approach to the theory of relaxing polymeric media
,”
J. Chem. Phys.
14
(
2
),
80
92
(
1946
).
10.
Henderson
,
K. J.
,
T. C.
Zhou
,
K. J.
Otim
, and
K. R.
Shull
, “
Ionically cross-linked triblock copolymer hydrogels with high strength
,”
Macromolecules
43
(
14
),
6193
6201
(
2010
).
11.
Holten-Andersen
,
N.
,
M. J.
Harrington
,
H.
Birkedal
,
B. P.
Lee
,
P.
Messersmith
,
K. Y. C.
Lee
, and
J. H.
Waite
, “
pH-induced metal-ligand cross-links inspired by mussel yield self-healing polymer networks with near-covalent elastic moduli
,”
Proc. Natl. Acad. Sci. U.S.A.
108
(
7
),
2651
2655
(
2011
).
12.
Indei
,
T.
, and
J.
Takimoto
, “
Linear viscoelastic properties of transient networks formed by associating polymers with multiple stickers
,”
J. Chem. Phys.
133
,
194902
(
2010
).
13.
Janmey
,
P. A.
,
M. E.
McCormick
,
S.
Rammensee
,
J. L.
Leight
,
P. C.
Georges
, and
F. C.
MacKintosh
, “
Negative normal stress in semiflexible biopolymer gels
,”
Nat. Mater.
6
,
48
51
(
2007
).
14.
Keita
,
G.
,
A.
Richard
,
R.
Audebert
,
E.
Pezron
, and
L.
Leibler
, “
The poly(vinyl alcohol)-borate system: Influence of polyelectrolyte effects on phase diagrams
,”
Polymer
36
(
3
),
49
54
(
1995
).
15.
Koike
,
A.
,
N.
Nemoto
,
T.
Inoue
, and
K.
Osaki
, “
Dynamic light scattering and dynamic viscoelasticity of Poly(vinyl alcohol) in aqueous borax solutions. 1. Concentration effect
,”
Macromolecules
28
(
7
),
2339
2344
(
1995
).
16.
Kurokawa
,
H.
,
M.
Shibayama
,
T.
Ishimaru
, and
S.
Namura
, “
Phase behaviour and sol-gel transition of poly(vinyl alcohol)-borate complex in aqueous solution
,”
Polymer
33
(
10
),
2182
2188
(
1992
).
17.
Lee
,
K. Y.
, and
D. J.
Mooney
, “
Hydrogels for tissue engineering
,”
Chem. Rev.
101
(
7
),
1869
1879
(
2001
).
18.
Leibler
,
L.
,
M.
Rubinstein
, and
R. H.
Colby
, “
Dynamics of reversible networks
,”
Macromolecules
24
(
16
),
4701
4707
(
1991
).
19.
Leibler
,
L.
,
P.
Erwoan
, and
P. A.
Pincus
, “
Viscosity behaviour of polymer solutions in the presence of complexing ions
,”
Polymer
29
(
6
),
1105
1109
(
1988
).
20.
Li
,
J.
,
Z.
Suo
, and
J. J.
Vlassak
, “
Stiff, strong, and tough hydrogels with good chemical stability
,”
J. Mater. Chem. B
2
(
39
),
6708
6713
(
2014
).
21.
Li
,
L.
,
B.
Yan
,
J.
Yang
,
L.
Chen
, and
H.
Zeng
, “
Novel mussel-inspired injectable self-healing hydrogel with anti-biofouling property
,”
Adv. Mater.
27
(
7
),
1294
1299
(
2015
).
22.
Lin
,
W. C.
,
W.
Fan
,
A.
Marcellan
,
D.
Hourdet
, and
C.
Creton
, “
Large strain and fracture properties of poly(dimethylacrylamide)/silica hybrid hydrogels
,”
Macromolecules
43
(
5
),
2554
2563
(
2010
).
23.
Long
,
R.
,
K.
Mayumi
,
C.
Creton
,
T.
Narita
, and
C. Y.
Hui
, “
Time dependent behavior of a dual cross-link self-healing gel: Theory and experiments
,”
Macromolecules
47
(
20
),
7243
7250
(
2014
).
24.
Mayumi
,
K.
,
A.
Marcellan
,
G.
Ducouret
,
C.
Creton
, and
T.
Narita
, “
Stress-strain relationship of highly stretchable dual cross-link gels: Separability of strain and time effect
,”
ACS Macro Lett.
2
(
12
),
1065
1068
(
2013
).
25.
Meyvis
,
T. K. L.
,
S. C.
De Smedt
,
J.
Demeester
, and
W. E.
Hennink
, “
Rheological monitoring of long-term degrading polymer hydrogels
,”
J. Rheol.
43
(
4
),
933
950
(
1999
).
26.
Mihai
,
L. A.
, and
A.
Goriely
, “
Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials
,”
Proc. R. Soc. London, Ser. A
467
,
3633
3646
(
2011
).
27.
Munster
,
S.
,
L. M.
Jawerth
,
B. A.
Leslie
,
J. I.
Weitz
,
B.
Fabry
, and
D. A.
Weitz
, “
Strain history dependence of the nonlinear stress response of fibrin and collagen networks
,”
Proc. Natl. Acad. Sci. U.S.A.
110
(
30
),
12197
12202
(
2013
).
28.
Narita
,
T.
,
K.
Mayumi
,
G.
Ducouret
, and
P.
Hebraud
, “
Viscoelastic properties of Poly(vinyl alcohol) hydrogels having permanent and transient cross-links studied by microrheology, classical rheometry, and dynamic light scattering
,”
Macromolecules
46
(
10
),
4174
4183
(
2013
).
29.
Nemoto
,
N.
,
A.
Koike
, and
K.
Osaki
, “
Dynamic light scattering and dynamic viscoelasticity of Poly(vinyl alcohol) in aqueous borax solutions. 2. Polymer concentration and molecular weight effects
,”
Macromolecules
29
(
5
),
1445
1451
(
1996
).
30.
Peak
,
C.
,
J.
Wilker
, and
G.
Schmidt
, “
A review on tough and sticky hydrogels
,”
Colloid Polym. Sci.
291
(
9
),
2031
2047
(
2013
).
31.
Peppas
,
N.
, and
J. J.
,
Sahlin
, “
Hydrogels as mucoadhesive and bioadhesive materials: A review
,”
Biomaterials
17
(
16
),
1553
1561
(
1996
).
32.
Pritchard
,
R. H.
,
Y. Y. S.
Huang
, and
E. M.
Terentjev
, “
Mechanics of biological networks: Form the cell cytoskeleton to connective tissue
,”
Soft Matter
10
,
1864
1884
(
2014
).
33.
Rivlin
,
R. S.
, “
Large elastic deformations of isotropic materials. VII. Experiments on the deformation of rubber
,”
Philos. Trans. R. Soc. London, Ser. A
243
(
865
),
251
288
(
1951
).
34.
Rubinstein
,
M.
, and
A. N.
Semenov
, “
Dynamics of entangled solutions of associating polymers
,”
Macromolecules
34
(
4
),
1058
1068
(
2001
).
35.
Rubinstein
,
M.
, and
R.
Colby
,
Polymer Physics
(
Oxford University
,
New York
,
2003
).
36.
Savins
,
J. G.
, “
Shear thickening phenomena in poly(vinyl)alcohol-borate complexes
,”
Rheol. Acta
7
(
1
),
87
93
(
1968
).
37.
Shibayama
,
M.
,
T.
Takeuchi
, and
S.
Nomura
, “
Swelling/shrinking and dynamic light scattering studies on chemically cross-linked poly(vinyl alcohol) gels in the presence of borate ions
,”
Macromolecules
27
(
9
),
5350
5358
(
1994
).
38.
Storm
,
C.
,
J. J.
Pastore
,
F. C.
MacKintosh
,
T. C.
Lubensky
, and
P. A.
Janmey
, “
Nonlinear elasticity in biological gels
,”
Nature
435
,
191
194
(
2005
).
39.
Sun
,
J. Y.
,
X.
Zhao
,
W. R.
Illeperuma
,
O.
Chaudhuri
,
K. H.
Oh
,
D. J.
Mooney
,
J. J.
Vlassak
, and
Z.
Suo
, “
Highly stretchable and tough hydrogels
,”
Nature
489
,
133
136
(
2012
).
40.
Sun
,
T. L.
,
T.
Kurokawa
,
S.
Kuroda
,
A. B.
Ihsan
,
I.
Akasaki
,
K.
Sato
,
M. A.
Haque
,
T.
Nakajima
, and
J. P.
Gong
, “
Physical hydrogels composed of polyampholytes demonstrate high toughness and viscoelasticity
,”
Nat. Mater.
12
,
932
937
(
2013
).
41.
Tanaka
,
F.
, and
S. F.
Edwards
, “
Viscoelastic properties of physically cross-linked networks. Transient network theory
,”
Macromolecules
25
(
5
),
1516
1523
(
1992
).
42.
Webber
,
R. E.
,
C.
Creton
,
H. R.
Brown
, and
J. P.
Gong
, “
Large strain hysteresis and Mullin's effect of tough double-network hydrogels
,”
Macromolecules
40
(
8
),
2919
2927
(
2007
).
43.
Wolff
,
L.
, and
K.
Kroy
, “
Minimal model for the inelastic mechanics of biopolymer networks and cells
,”
Phys. Rev. E
86
(
4
),
040901
(
2012
).
44.
Zhao
,
X.
, “
Multi-scale multi-mechanism design of tough hydrogels: building dissipation into stretchy networks
,”
Soft Matter
10
(
5
),
672
687
(
2014
).
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