Linear viscoelasticity is analyzed for unentangled sulfonated polystyrene ionomer samples, SPS-X, neutralized with transitional bivalent metal ions (with X = Zn2+, Mn2+, Co2+, and Ni2+). Two model systems, with the degree of gelation slightly above the gel point (1.0 mol. %) and close to the full gelation point (1.6 mol. %), are chosen. For either system, the amplitude of plateau is insensitive to, while the terminal relaxation time is highly dependent on, the degree of neutralization. The terminal relaxation time first increases, but then decreases with the increase in the degree of neutralization. This trend is discussed with respect to the difference in dissociation rates between the acidic, ionic associations and free salts that coexist in the ion aggregates. The transition point, where the terminal relaxation time achieves the highest value, occurs at the stoichiometric point for Zn2+, but is higher than the stoichiometric point for Mn2+, Co2+, and Ni2+. Both the ion content at the transition point and the terminal relaxation time follow the order of SPS-Ni > SPS-Co > SPS-Mn > SPS-Zn. This order contrasts with SPS-X with alkali counterions where the transition point is consistently the stoichiometric point and the terminal relaxation time increases with the decrease in the counterion size. We attribute this order to the different filling statuses of the electrons in the 3d orbital for these SPS-X samples.

1.
Castagna
,
A. M.
,
W. Q.
Wang
,
K. I.
Winey
, and
J.
Runt
, “
Influence of the degree of sulfonation on the structure and dynamics of sulfonated polystyrene copolymers
,”
Macromolecules
43
,
10498
10504
(
2010
).
2.
Castagna
,
A. M.
,
W. Q.
Wang
,
K. I.
Winey
, and
J.
Runt
, “
Structure and dynamics of zinc-neutralized sulfonated polystyrene ionomers
,”
Macromolecules
44
,
2791
2798
(
2011
).
3.
Castagna
,
A. M.
,
W. Q.
Wang
,
K. I.
Winey
, and
J.
Runt
, “
Influence of cation type on structure and dynamics in sulfonated polystyrene ionomers
,”
Macromolecules
44
,
5420
5426
(
2011
).
4.
Nishida
,
M.
, and
A.
Eisenberg
, “
Dynamic mechanical study of sodium sulfonated random ionomers based on hydrogenated styrene butadiene copolymer
,”
Macromolecules
29
,
1507
1515
(
1996
).
5.
Leibler
,
L.
,
M.
Rubinstein
, and
R. H.
Colby
, “
Dynamics of reversible networks
,”
Macromolecules
24
,
4701
4707
(
1991
).
6.
Rubinstein
,
M.
, and
A. N.
Semenov
, “
Thermoreversible gelation in solutions of associating polymers. 2. Linear dynamics
,”
Macromolecules
31
,
1386
1397
(
1998
).
7.
Chen
,
Q.
,
G. J.
Tudryn
, and
R. H.
Colby
, “
Ionomer dynamics and the sticky Rouse model
,”
J. Rheol.
57
,
1441
1462
(
2013
).
8.
Yang
,
H.
,
S.
Ghiassinejad
,
E.
van Ruymbeke
, and
C. A.
Fustin
, “
Tunable interpenetrating polymer network hydrogels based on dynamic covalent bonds and metal-ligand bonds
,”
Macromolecules
53
,
6956
6967
(
2020
).
9.
Zhang
,
X. Y.
,
Y.
Vidavsky
,
S.
Aharonovich
,
S. J.
Yang
,
M. R.
Buche
,
C. E.
Diesendruck
, and
M. N.
Silberstein
, “
Bridging experiments and theory: Isolating the effects of metal-ligand interactions on viscoelasticity of reversible polymer networks
,”
Soft Matter
16
,
8591
8601
(
2020
).
10.
Li
,
J. J.
,
X.
Cao
,
Y. G.
Liu
, and
Q.
Chen
, “
Thermorheological complexity of poly(vinyl alcohol)/borax aqueous solutions
,”
J. Rheol.
64
,
991
1002
(
2020
).
11.
Chen
,
Q.
,
C. W.
Huang
,
R. A.
Weiss
, and
R. H.
Colby
, “
Viscoelasticity of reversible gelation for ionomers
,”
Macromolecules
48
,
1221
1230
(
2015
).
12.
Baxandall
,
L. G.
, “
Dynamics of reversibly cross-linked chains
,”
Macromolecules
22
,
1982
1988
(
1989
).
13.
Chen
,
Q.
, and
R. H.
Colby
, “
Linear viscoelasticity of sulfonated styrene oligomers near the sol-gel transition
,”
Korea-Aust. Rheol. J.
26
,
257
261
(
2014
).
14.
Huang
,
C. W.
,
C.
Wang
,
Q.
Chen
,
R. H.
Colby
, and
R. A.
Weiss
, “
Reversible gelation model predictions of the linear viscoelasticity of oligomeric sulfonated polystyrene ionomer blends
,”
Macromolecules
49
,
3936
3947
(
2016
).
15.
Zhang
,
Z. J.
,
C.
Liu
,
X.
Cao
,
L. C.
Gao
, and
Q.
Chen
, “
Linear viscoelastic and dielectric properties of strongly hydrogen-bonded polymers near the sol-gel transition
,”
Macromolecules
49
,
9192
9202
(
2016
).
16.
Huang
,
C. W.
,
Q.
Chen
, and
R. A.
Weiss
, “
Nonlinear rheology of random sulfonated polystyrene ionomers: The role of the sol-gel transition
,”
Macromolecules
49
,
9203
9214
(
2016
).
17.
Zhang
,
Z. J.
,
Q.
Chen
, and
R. H.
Colby
, “
Dynamics of associative polymers
,”
Soft Matter
14
,
2961
2977
(
2018
).
18.
Chen
,
Q.
,
N. Q.
Bao
,
J. H. H.
Wang
,
T.
Tunic
,
S. W.
Liang
, and
R. H.
Colby
, “
Linear viscoelasticity and dielectric spectroscopy of ionomer/plasticizer mixtures: A transition from ionomer to polyelectrolyte
,”
Macromolecules
48
,
8240
8252
(
2015
).
19.
Chen
,
Q.
,
H.
Masser
,
H. S.
Shiau
,
S. W.
Liang
,
J.
Runt
,
P. C.
Painter
, and
R. H.
Colby
, “
Linear viscoelasticity and Fourier transform infrared spectroscopy of polyether-ester-sulfonate copolymer ionomers
,”
Macromolecules
47
,
3635
3644
(
2014
).
20.
Chen
,
Q.
,
Z. J.
Zhang
, and
R. H.
Colby
, “
Viscoelasticity of entangled random polystyrene ionomers
,”
J. Rheol.
60
,
1031
1040
(
2016
).
21.
Colby
,
R. H.
,
X.
Zheng
,
M. H.
Rafailovich
,
J.
Sokolov
,
D. G.
Peiffer
,
S. A.
Schwarz
,
Y.
Strzhemechny
, and
D.
Nguyen
, “
Dynamics of lightly sulfonated polystyrene ionomers
,”
Phys. Rev. Lett.
81
,
3876
3879
(
1998
).
22.
Rees
,
R. W.
, Patent No. US3338739 (
1967
).
23.
Molitor
,
R. P.
, Patent No. US3819768 (
1974
).
24.
Zhang
,
L. H.
,
N. R.
Brostowitz
,
K. A.
Cavicchi
, and
R. A.
Weiss
, “
Perspective: Ionomer research and applications
,”
Macromol. React. Eng.
8
,
81
99
(
2014
).
25.
Mueller
,
D. G.
, “
Surlyn ionomer resin used as dynamic ankle orthoses in the not (Bobath) approach to neurologic patients
,”
Phys. Ther.
67
,
773
773
(
1987
).
26.
Nishio
,
M.
,
A.
Nishioka
,
T.
Taniguchi
, and
K.
Koyama
, “
Rheological properties of ethylene ionomer neutralized with binary metal cation
,”
Polymer
46
,
261
266
(
2005
).
27.
Eisenberg
,
A.
,
B.
Hird
, and
R. B.
Moore
, “
A new multiplet-cluster model for the morphology of random ionomers
,”
Macromolecules
23
,
4098
4107
(
1990
).
28.
Poulakis
,
J. G.
, and
C. D.
Papaspyrides
, “
A model process for the recycling of a Surlyn® ionomer
,”
Adv. Polym. Technol.
19
,
203
209
(
2000
).
29.
Vanhoorne
,
P.
, and
R. A.
Register
, “
Low-shear melt rheology of partially-neutralized ethylene-methacrylic acid ionomers
,”
Macromolecules
29
,
598
604
(
1996
).
30.
Tomkovic
,
T.
, and
S. G.
Hatzikiriakos
, “
Nonlinear rheology of poly(ethylene-co-methacrylic acid) ionomers
,”
J. Rheol.
62
,
1319
1329
(
2018
).
31.
Huang
,
C. W.
,
Q.
Chen
, and
R. A.
Weiss
, “
Rheological behavior of partially neutralized oligomeric sulfonated polystyrene ionomers
,”
Macromolecules
50
,
424
431
(
2017
).
32.
Weiss
,
R. A.
, and
H. Y.
Zhao
, “
Rheological behavior of oligomeric ionomers
,”
J. Rheol.
53
,
191
213
(
2009
).
33.
Zhang
,
Z. J.
,
C. W.
Huang
,
R. A.
Weiss
, and
Q.
Chen
, “
Association energy in strongly associative polymers
,”
J. Rheol.
61
,
1199
1207
(
2017
).
34.
Eisenberg
,
A.
, and
J.-S.
Kim
,
Introduction to Ionomers
(
Wiley
,
New York
,
1998
).
35.
Stukalin
,
E. B.
,
L. H.
Cai
,
N. A.
Kumar
,
L.
Leibler
, and
M.
Rubinstein
, “
Self-healing of unentangled polymer networks with reversible bonds
,”
Macromolecules
46
,
7525
7541
(
2013
).
36.
Gold
,
B. J.
,
C. H.
Hövelmann
,
N.
Lühmann
,
N. K.
Székely
,
W.
Pyckhout-Hintzen
,
A.
Wischnewski
, and
D.
Richter
, “
Importance of compact random walks for the rheology of transient networks
,”
ACS Macro Lett.
6
,
73
77
(
2017
).
37.
Amin
,
D.
,
A. E.
Likhtman
, and
Z.
Wang
, “
Dynamics in supramolecular polymer networks formed by associating telechelic chains
,”
Macromolecules
49
,
7510
7524
(
2016
).
38.
Frischknecht
,
A. L.
, and
K. I.
Winey
, “
The evolution of acidic and ionic aggregates in ionomers during microsecond simulations
,”
J. Chem. Phys.
150
,
064901
(
2019
).
39.
Lodge
,
T. P.
,
C. L.
Seitzinger
,
S. C.
Seeger
,
S.
Yang
,
S.
Gupta
, and
K. D.
Dorfman
, “
Dynamics and equilibration mechanisms in block copolymer particles
,”
ACS Polym. Au
2
,
397
416
(
2022
).
40.
Qiao
,
X. Y.
,
X. Y.
Wang
,
C.
Wang
, and
R. A.
Weiss
, “
Effect of zinc stearate on the properties of a sulfonated polystyrene ionomer
,”
J. Rheol.
62
,
821
830
(
2018
).
41.
Zhang
,
L. H.
,
B. C.
Katzenmeyer
,
K. A.
Cavicchi
,
R. A.
Weiss
, and
C.
Wesdemiotis
, “
Sulfonation distribution in sulfonated polystyrene ionomers measured by MALDI-ToF MS
,”
ACS Macro Lett.
2
,
217
221
(
2013
).
42.
Cao
,
X.
,
L.
Peng
,
X. B.
Huang
, and
Q.
Chen
, “
A trade-off between hardness and stretchability of associative networks during the sol-to-gel transition
,”
J. Rheol.
67
,
1119
1128
(
2023
).
43.
Cao
,
X.
,
X. Y.
Yu
,
J.
Qin
, and
Q.
Chen
, “
Reversible gelation of entangled ionomers
,”
Macromolecules
52
,
8771
8780
(
2019
).
44.
Fetters
,
L. J.
,
D. J.
Lohse
, and
R. H.
Colby
, Chain dimensions and entanglement spacings, in
Physical Properties of Polymers Handbook
, edited by
J. E.
Mark
(
Springer
,
New York
,
2007
), Chap. 25 pp.
447
454
.
45.
Pei
,
Y. X.
,
Q.
Chen
,
Y.
Matsumiya
, and
H.
Watanabe
, “
Nonlinear relaxation of unentangled associative polymers: Strain-induced hardening and softening
,”
Macromolecules
58
,
953
967
(
2025
).
46.
Orwoll
,
R. A.
, Densities, Coefficients of Thermal Expansion, and Compressibilities of Amorphous Polymers, in
Physical Properties of Polymers Handbook
, edited by
J. E.
Mark
(
Springer
,
New York
,
2007
), Chap. 7 pp.
93
101
.
47.
Register
,
R. A.
, and
S. L.
Cooper
, “
Anomalous small-angle x-ray scattering from nickel-neutralized ionomers. 1. Amorphous polymer matrixes
,”
Macromolecules
23
,
310
317
(
1990
).
48.
Yarusso
,
D. J.
, and
S. L.
Cooper
, “
Microstructure of ionomers: Interpretation of small-angle x-ray scattering data
,”
Macromolecules
16
,
1871
1880
(
1983
).
49.
Mohottalalage
,
S. S.
,
C.
Kosgallana
,
S.
Meedin
,
T. C.
O’Connor
,
G. S.
Grest
, and
D.
Perahia
, “
Response of sulfonated polystyrene melts to nonlinear elongation flows
,”
Macromolecules
56
,
947
953
(
2023
).
50.
Cao
,
Y.
,
Q. L.
Yuan
,
Q.
Chen
, and
W. S.
Xu
, “
Influence of charge interaction strength and counterion size on the structure and dynamics of simulated telechelic ionomer melts
,”
Macromolecules
58
,
2829
2849
(
2025
).
51.
He
,
Q. B.
,
Y. J.
Zhang
,
H. L.
Li
, and
Q.
Chen
, “
Rheological properties of ABA-type copolymers physically end-cross-linked by polyoxometalate
,”
Macromolecules
53
,
10927
10941
(
2020
).
52.
Yan
,
T.
,
K.
Schröter
,
F.
Herbst
,
W. H.
Binder
, and
T.
Thurn-Albrecht
, “
What controls the structure and the linear and nonlinear rheological properties of dense, dynamic supramolecular polymer networks?
,”
Macromolecules
50
,
2973
2985
(
2017
).
53.
Bagrodia
,
S.
, and
G. L.
Wilkes
, “
Comments on the effect of cation, type on ionomer properties
,”
Polym. Bull.
12
,
389
392
(
1984
).
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