Everyone can observe the peculiar effect of water on a sponge: upon drying, a sponge shrinks and stiffens; it swells and softens upon wetting. In this work, we aim to explain and model this behavior by using the Biot–Coussy poromechanical framework. We measure the volume and the bulk modulus of sponges at different water contents. Upon drying, the volume of the sponge decreases by more than half and its bulk modulus increases by almost two orders of magnitude. We develop a partially saturated microporomechanical model of the sponge undergoing finite transformations. The model compares well with the experimental data. We show that about half of the stiffening of the sponge upon drying is due to geometrical nonlinearities induced by a closing of the pores under the action of capillary pressure. The other half of the stiffening can be explained by the nonlinear elastic properties of the cellulose material itself.

References

References
1.
O'Sullivan
,
A. C.
,
1997
, “
Cellulose: The Structure Slowly Unravels
,”
Cellulose
,
4
(
3
), pp.
173
207
.10.1023/A:1018431705579
2.
Purves
,
C. B.
,
1954
,
Chain Structure in Cellulose and Cellulose Derivatives: Part 1
,
Wiley-
Interscience,
New York
.
3.
Sjöström
,
E.
,
1981
,
Wood Chemistry Fundamentals and Applications
,
Academic
,
New York
.
4.
Tashiro
,
K.
, and
Kobayashi
,
M.
,
1991
, “
Theoretical Evaluation of Three-Dimensional Elastic Constants of Native and Regenerated Celluloses: Role of Hydrogen Bonds
,”
Polymer
,
32
(
8
), pp.
1516
1526
.10.1016/0032-3861(91)90435-L
5.
Hinterstoisser
,
B.
,
Akerholm
,
M.
, and
Salmén
,
L.
,
2001
, “
Effect of Fiber Orientation in Dynamic FTIR Study on Native Cellulose
,”
Carbohydr. Res.
,
334
(
1
), Aug., pp.
27
37
.10.1016/S0008-6215(01)00167-7
6.
Akerholm
,
M.
,
Hinterstoisser
,
B.
, and
Salmén
,
L.
,
2004
, “
Characterization of the Crystalline Structure of Cellulose Using Static and Dynamic FT-IR Spectroscopy
,”
Carbohydr. Res.
,
339
(
3
), pp.
569
578
.10.1016/j.carres.2003.11.012
7.
Tanaka
,
F.
, and
Fukui
,
N.
,
2004
, “
The Behavior of Cellulose Molecules in Aqueous Environments
,”
Cellulose
,
11
(
1
), pp.
33
38
.10.1023/B:CELL.0000014769.01795.7f
8.
Luukko
,
K.
, and
Maloney
,
T. C.
,
1999
, “
Swelling of Mechanical Pulp Fines
,”
Cellulose
,
6
(
2
), pp.
123
135
.10.1023/A:1009256307149
9.
Scallan
,
A. M.
, and
Grignon
,
J.
,
1979
, “
Effect of Cations on Pulp and Paper Properties
,”
Svensk Papperstidning-nordisk Cellulosa
,
82
(
2
), pp.
40
47
.
10.
Lindström
,
T.
, and
Carlsson
,
G.
,
1982
, “
The Effect of Chemical Environment on Fiber Swelling
,”
Svensk Papperstidning-nordisk Cellulosa
,
85
, pp.
R14
R20
.
11.
Scallan
,
A. M.
, and
Tigerström
,
A. C.
,
1992
, “
Swelling and Elasticity of the Cell-Walls of Pulp Fibers
,”
J. Pulp Pap. Sci.
,
18
(
5
), pp.
J188
J193
.
12.
Sahin
,
H. T.
, and
Arslan
,
M. B.
,
2008
, “
A Study on Physical and Chemical Properties of Cellulose Paper Immersed in Various Solvent Mixtures
,”
Int. J. Mol. Sci.
,
9
(
1
), pp.
78
88
.10.3390/ijms9010078
13.
Hofstetter
,
K.
,
Hinterstoisser
,
B.
, and
Salmén
,
L.
,
2006
, “
Moisture Uptake in Native Cellulose—The Roles of Different Hydrogen Bonds: A Dynamic FT-IR Study Using Deuterium Exchange
,”
Cellulose
,
13
(
2
), pp.
131
145
.10.1007/s10570-006-9055-2
14.
Hatakeyama
,
H.
, and
Hatakeyama
,
T.
,
1998
, “
Interaction Between Water and Hydrophilic Polymers
,”
Thermochim. Acta
,
308
(
1–2
), pp.
3
22
.10.1016/S0040-6031(97)00325-0
15.
Eichhorn
,
S. J.
,
Baillie
,
C. A.
,
Zafeiropoulos
,
N.
,
Mwaikambo
,
L. Y.
,
Ansell
,
M. P.
,
Dufresne
,
A.
,
Entwistle
,
K. M.
,
Herrera-Franco
,
P. J.
,
Escamilla
,
G. C.
,
Groom
,
L.
,
Hughes
,
M.
,
Hill
,
C.
,
Rials
,
T. G.
, and
Wild
,
P. M.
,
2001
, “
Review: Current International Research Into Cellulosic Fibres and Composites
,”
J. Mater. Sci.
,
36
(
9
), pp.
2107
2131
.10.1023/A:1017512029696
16.
Myllytie
,
P.
,
Salmén
,
L.
,
Haimi
,
E.
, and
Laine
,
J.
,
2009
, “
Viscoelasticity and Water Plasticization of Polymer-Cellulose Composite Films and Paper Sheets
,”
Cellulose
,
17
(
2
), pp.
375
385
.10.1007/s10570-009-9376-z
17.
Coussy
,
O.
,
2010
,
Mechanics and Physics of Porous Solids
,
Wiley
,
New York
.
18.
Wittman
,
F.
,
1968
, “
Surface Tension, Shrinkage and Strength of Hardened Cement Paste
,”
Mater. Struct. (in French: Matériaux et Constructions)
,
1
(
6
), pp.
547
552
.10.1007/BF02473643
19.
Coussy
,
O.
,
2004
,
Poromechanics
,
Wiley
,
New York
.
20.
Dormieux
,
L.
,
Kondo
,
D.
, and
Ulm
,
F.-J.
,
2006
,
Microporomechanics
,
Wiley
,
New York
.
21.
Brochard
,
L.
,
Vandamme
,
M.
, and
Pellenq
,
R.-M.
,
2012
, “
Poromechanics of Microporous Media
,”
J. Mech. Phys. Solids
,
60
(
4
), pp.
606
622
.10.1016/j.jmps.2012.01.001
You do not currently have access to this content.