A poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (Pluronic F127) micelle system was stabilized using an ultraviolet-induced semi-interpenetrating network (sIPN). The sIPN structure within the micelle cores was found to stabilize the micelles against low temperatures, but affected the resulting material properties. In this study, the rheological properties of Pluronic F127 with sIPN (F127-sIPN) and without sIPN (F127) were compared. The presence of the sIPN structure increased the gelation temperature (Tgel) at the same concentration, and unlike F127, F127-sIPN exhibited strong heating rate dependent and thermodynamically irreversible behaviors. Hard gels containing various concentrations of F127-sIPN and F127 were investigated at 40 °C. At concentrations above 18 wt. %, both F127-sIPN and F127 exhibited similar linear viscoelastic properties due to the tight, ordered core–shell micelles packing, but the two systems exhibited different behaviors below 18 wt. % concentration. To investigate this difference, hard gels with 16 wt. % F127-sIPN and F127 were selected, and two types of nonlinear rheological tests were conducted, i.e., large amplitude oscillatory shear (LAOS) and strain-rate frequency superposition (SRFS) tests. The cage modulus of F127-sIPN obtained from LAOS testing showed it maintained its elastic contribution over the large deformation region meaning that a loose core network still existed. The relaxation time spectrum of F127-sIPN obtained by SRFS testing indicated it had two relaxation modes (fast and slow) whereas that for F127 had only a fast mode. The slow relaxation mode of F127-sIPN is associated with crosslinking of the sIPN. Since these behaviors were not observed in linear rheological tests, it was concluded that nonlinear rheological tests provide more structural information about hard gels.

1.
Malmsten
,
M.
, and
B.
Lindman
, “
Self-assembly in aqueous block copolymer solutions
,”
Macromolecules
25
(
20
),
5440
5445
(
1992
).
2.
Linse
,
P.
, “
Phase behavior of poly(ethylene oxide)-poly(propylene oxide) block copolymers in aqueous solution
,”
J. Phys. Chem.
97
(
51
),
13896
13902
(
1993
).
3.
Alexandridis
,
P.
, and
T.
Alan Hatton
, “
Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer surfactants in aqueous solutions and at interfaces: Thermodynamics, structure, dynamics, and modeling
,”
Colloids Surf. A Physicochem. Eng. Asp.
96
(
1–2
),
1
46
(
1995
).
4.
Wanka
,
G.
,
H.
Hoffmann
, and
W.
Ulbricht
, “
The aggregation behavior of poly-(oxyethylene)-poly-(oxypropylene)-poly-(oxyethylene)-block-copolymers in aqueous solution
,”
Colloid Polym. Sci.
268
(
2
),
101
117
(
1990
).
5.
Wanka
,
G.
,
H.
Hoffmann
, and
W.
Ulbricht
, “
Phase diagrams and aggregation behavior of poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) triblock copolymers in aqueous solutions
,”
Macromolecules
27
(
15
),
4145
4159
(
1994
).
6.
Mortensen
,
K.
, and
J. S.
Pedersen
, “
Structural study on the micelle formation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer in aqueous solution
,”
Macromolecules
26
(
4
),
805
812
(
1993
).
7.
Alexandridis
,
P.
,
J. F.
Holzwarth
, and
T. A.
Hatton
, “
Micellization of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers in aqueous solutions: Thermodynamics of copolymer association
,”
Macromolecules
27
(
9
),
2414
2425
(
1994
).
8.
Wu
,
G.
,
B.
Chu
, and
D. K.
Schneider
, “
SANS study of the micellar structure of PEO/PPO/PEO aqueous solution
,”
J. Phys. Chem.
99
(
14
),
5094
5101
(
1995
).
9.
Glatter
,
O.
,
G.
Scherf
,
K.
Schillen
, and
W.
Brown
, “
Characterization of a poly(ethylene oxide)-poly(propylene oxide) triblock copolymer (EO27-PO39-EO27) in aqueous solution
,”
Macromolecules
27
(
21
),
6046
6054
(
1994
).
10.
Hvidt
,
S.
,
E. B.
Joergensen
,
W.
Brown
, and
K.
Schillen
, “
Micellization and gelation of aqueous solutions of a triblock copolymer studied by rheological techniques and scanning calorimetry
,”
J. Phys. Chem.
98
(
47
),
12320
12328
(
1994
).
11.
Bahadur
,
P.
, and
K.
Pandya
, “
Aggregation behavior of Pluronic P-94 in water
,”
Langmuir
8
(
11
),
2666
2670
(
1992
).
12.
Bieze
,
T. W. N.
,
A. C.
Barnes
,
C. J. M.
Huige
,
J. E.
Enderby
, and
J. C.
Leyte
, “
Distribution of water around poly(ethylene oxide): A neutron diffraction study
,”
J. Phys. Chem.
98
(
26
),
6568
6576
(
1994
).
13.
Rassing
,
J.
, and
D.
Attwood
, “
Ultrasonic velocity and light-scattering studies on the polyoxyethylene—polyoxypropylene copolymer Pluronic F127 in aqueous solution
,”
Int. J. Pharm.
13
(
1
),
47
55
(
1982
).
14.
Vadnere
,
M.
,
G.
Amidon
,
S.
Lindenbaum
, and
J.
Haslam
, “
Thermodynamic studies on the gel-sol transition of some pluronic polyols
,”
Int. J. Pharm.
22
(
2–3
),
207
218
(
1984
).
15.
Lam
,
Y.-M.
, and
G.
Goldbeck-Wood
, “
Mesoscale simulation of block copolymers in aqueous solution: Parameterisation, micelle growth kinetics and the effect of temperature and concentration morphology
,”
Polymer (Guildf)
44
(
12
),
3593
3605
(
2003
).
16.
Mortensen
,
K.
,
W.
Brown
, and
B.
Nordén
, “
Inverse melting transition and evidence of three-dimensional cubatic structure in a block-copolymer micellar system
,”
Phys. Rev. Lett.
68
(
15
),
2340
2343
(
1992
).
17.
Mortensen
,
K.
, “
Phase behaviour of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock-copolymer dissolved in water
,”
Europhys. Lett.
19
(
7
),
599
604
(
1992
).
18.
Mortensen
,
K.
,
W.
Batsberg
, and
S.
Hvidt
, “
Effects of PEO−PPO diblock impurities on the cubic structure of aqueous PEO−PPO−PEO pluronics micelles: fcc and bcc ordered structures in F127
,”
Macromolecules
41
(
5
),
1720
1727
(
2008
).
19.
Jiang
,
J.
,
C.
Burger
,
C.
Li
,
J.
Li
,
M. Y.
Lin
,
R. H.
Colby
,
M. H.
Rafailovich
, and
J. C.
Sokolov
, “
Shear-induced layered structure of polymeric micelles by SANS
,”
Macromolecules
40
(
11
),
4016
4022
(
2007
).
20.
Cohn
,
D.
,
H.
Sagiv
,
A.
Benyamin
, and
G.
Lando
, “
Engineering thermoresponsive polymeric nanoshells
,”
Biomaterials
30
(
19
),
3289
96
(
2009
).
21.
Petrov
,
P.
,
M.
Bozukov
, and
C. B.
Tsvetanov
, “
Innovative approach for stabilizing poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) micelles by forming nano-sized networks in the micelle
,”
J. Mater. Chem.
15
(
14
),
1481
1486
(
2005
).
22.
Yong
,
C. S.
,
J. S.
Choi
,
Q.-Z.
Quan
,
J.-D.
Rhee
,
C.-K.
Kim
,
S.-J.
Lim
,
K.-M.
Kim
,
P.-S.
Oh
, and
H.-G.
Choi
, “
Effect of sodium chloride on the gelation temperature, gel strength and bioadhesive force of poloxamer gels containing diclofenac sodium
,”
Int. J. Pharm.
226
(
1–2
),
195
205
(
2001
).
23.
Malmsten
,
M.
, and
B.
Lindman
, “
Effects of homopolymers on the gel formation in aqueous block copolymer solutions
,”
Macromolecules
26
(
6
),
1282
1286
(
1993
).
24.
Ivanova
,
R.
,
B.
Lindman
, and
P.
Alexandridis
, “
Evolution in structural polymorphism of pluronic F127 poly(ethylene oxide)−poly(propylene oxide) block copolymer in ternary systems with water and pharmaceutically acceptable organic solvents: From ‘glycols' to ‘oils'
,”
Langmuir
16
(
23
),
9058
9069
(
2000
).
25.
Ricci
,
E. J.
,
L. O.
Lunardi
,
D. M. A.
Nanclares
, and
J. M.
Marchetti
, “
Sustained release of lidocaine from Poloxamer 407 gels
,”
Int. J. Pharm.
288
(
2
),
235
44
(
2005
).
26.
Desai
,
S. D.
, and
J.
Blanchard
, “
Evaluation of pluronic F127-based sustained-release ocular delivery systems for pilocarpine using the albino rabbit eye model
,”
J. Pharm. Sci.
87
(
10
),
1190
11905
(
1998
).
27.
Antunes
,
F. E.
,
L.
Gentile
,
C. O.
Rossi
,
L.
Tavano
, and
G. A.
Ranieri
, “
Gels of Pluronic F127 and nonionic surfactants from rheological characterization to controlled drug permeation
,”
Colloids Surf. B. Biointerfaces
87
(
1
),
42
48
(
2011
).
28.
Rapoport
,
N.
, “
Stabilization and activation of Pluronic micelles for tumor-targeted drug delivery
,”
Colloids Surf. B: Biointerfaces
16
(
1–4
),
93
111
(
1999
).
29.
Torchilin
,
V. P.
, “
Structure and design of polymeric surfactant-based drug delivery systems
,”
J. Controlled Release
73
(
2–3
),
137
172
(
2001
).
30.
Torchilin
,
V. P.
, “
Multifunctional nanocarriers
,”
Adv. Drug Delivery Rev.
58
(
14
),
1532
1555
(
2006
).
31.
Petrov
,
P.
,
M.
Bozukov
,
M.
Burkhardt
,
S.
Muthukrishnan
,
A. H. E.
Muller
, and
C. B.
Tsvetanov
, “
Stabilization of polymeric micelles with a mixed poly(ethylene oxide)/poly(2-hydroxyethyl methacrylate) shell by formation of poly(pentaerythritol tetraacrylate) nanonetworks within the micelles
,”
J. Mater. Chem.
16
(
22
),
2192
2199
(
2006
).
32.
Kwak
,
M.
,
A. J.
Musser
,
J.
Lee
, and
A.
Herrmann
, “
DNA-functionalised blend micelles: Mix and fix polymeric hybrid nanostructures
,”
Chem. Commun. (Cambridge)
46
(
27
),
4935
4937
(
2010
).
33.
Prud'homme
,
R. K.
,
G.
Wu
, and
D. K.
Schneider
, “
Structure and rheology studies of poly(oxyethylene−oxypropylene−oxyethylene) aqueous solution
,”
Langmuir
12
(
20
),
4651
4659
(
1996
).
34.
Eiser
,
E.
,
F.
Molino
,
G.
Porte
, and
X.
Pithon
, “
Flow in micellar cubic crystals
,”
Rheol. Acta
39
(
3
),
201
208
(
2000
).
35.
Bahadur
,
P.
,
P.
Li
,
M.
Almgren
, and
W.
Brown
, “
Effect of potassium fluoride on the micellar behavior of Pluronic F-68 in aqueous solution
,”
Langmuir
8
(
8
),
1903
1907
(
1992
).
36.
Jørgensen
,
E. B.
,
S.
Hvidt
,
W.
Brown
, and
K.
Schillén
, “
Effects of salts on the micellization and gelation of a triblock copolymer studied by rheology and light scattering
,”
Macromolecules
30
(
8
),
2355
2364
(
1997
).
37.
Li
,
H.
,
G.-E.
Yu
,
C.
Price
,
C.
Booth
,
E.
Hecht
, and
H.
Hoffmann
, “
Concentrated aqueous micellar solutions of diblock copoly(oxyethylene/oxybutylene) E 41 B 8: A study of phase behavior
,”
Macromolecules
30
(
5
),
1347
1354
(
1997
).
38.
Hyun
,
K.
,
M.
Wilhelm
,
C. O.
Klein
,
K. S.
Cho
,
J. G.
Nam
,
K. H.
Ahn
,
S. J.
Lee
,
R. H.
Ewoldt
, and
G. H.
McKinley
, “
A review of nonlinear oscillatory shear tests: Analysis and application of large amplitude oscillatory shear (LAOS)
,”
Prog. Polym. Sci.
36
(
12
),
1697
1753
(
2011
).
39.
Hyun
,
K.
,
S. H.
Kim
,
K. H.
Ahn
, and
S. J.
Lee
, “
Large amplitude oscillatory shear as a way to classify the complex fluids
,”
J. Nonnewtonian Fluid Mech.
107
(
1–3
),
51
65
(
2002
).
40.
Hyun
,
K.
,
J. G.
Nam
,
M.
Wilhellm
,
K. H.
Ahn
, and
S. J.
Lee
, “
Large amplitude oscillatory shear behavior of PEO-PPO-PEO triblock copolymer solutions
,”
Rheol. Acta
45
(
3
),
239
249
(
2005
).
41.
McMullan
,
J. M.
, and
N. J.
Wagner
, “
Directed self-assembly of suspensions by large amplitude oscillatory shear flow
,”
J. Rheol.
53
(
3
),
575
588
(
2009
).
42.
Hamley
,
I. W.
,
J. A.
Pople
,
C.
Booth
,
L.
Derici
,
M.
Impéror-Clerc
, and
P.
Davidson
, “
Shear-induced orientation of the body-centered-cubic phase in a diblock copolymer gel
,”
Phys. Rev. E
58
(
6
),
7620
7628
(
1998
).
43.
López-Barrón
,
C. R.
,
L.
Porcar
,
A. P. R.
Eberle
, and
N. J.
Wagner
, “
Dynamics of melting and recrystallization in a polymeric micellar crystal subjected to large amplitude oscillatory shear flow
,”
Phys. Rev. Lett.
108
(
25
),
258301
(
2012
).
44.
Georgescauld
,
D.
,
J. P.
Desmazes
, and
H.
Duclohier
, “
Temperature dependence of the fluorescence of pyrene labeled crab nerve membranes
,”
Mol. Cell. Biochem.
27
(
3
),
147
153
(
1979
).
45.
Uchida
,
K.
, and
Y.
Takahashi
, “
Excimer and monomer emission of pyrene crystals associated with the phase transition
,”
Int. J. Quantum Chem.
18
(
1
),
301
305
(
1980
).
46.
Schmolka
,
I. R.
, “
Artificial skin I. Preparation and properties of pluronic F-127 gels for treatment of burns
,”
J. Biomed. Mater. Res.
6
(
6
),
571
582
(
1972
).
47.
Kwon
,
K.-W.
,
M. J.
Park
,
J.
Hwang
, and
K.
Char
, “
Effects of alcohol addition on gelation in aqueous solution of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer
,”
Polym. J.
33
(
5
),
404
410
(
2001
).
48.
Song
,
M. J.
,
D. S.
Lee
,
J. H.
Ahn
,
D. J.
Kim
, and
S. C.
Kim
, “
Dielectric behavior during sol-gel transition of PEO-PPO-PEO triblock copolymer aqueous solution
,”
Polym. Bull.
43
(
6
),
497
504
(
2000
).
49.
Park
,
M. J.
, and
K.
Char
, “
Two gel states of a PEO-PPO-PEO triblock copolymer formed by different mechanisms
,”
Macromol. Rapid Commun.
23
(
12
),
688
692
(
2002
).
50.
Brown
,
W.
,
K.
Schillen
,
M.
Almgren
,
S.
Hvidt
, and
P.
Bahadur
, “
Micelle and gel formation in a poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer in water solution: Dynamic and static light scattering and oscillatory shear measurements
,”
J. Phys. Chem.
95
(
4
),
1850
1858
(
1991
).
51.
Meznarich
,
N. A. K.
, and
B. J.
Love
, “
The Kinetics of Gel Formation for PEO−PPO−PEO triblock copolymer solutions and the effects of added methylparaben
,”
Macromolecules
44
(
9
),
3548
3555
(
2011
).
52.
Li
,
Y.
,
T.
Shi
,
Z.
Sun
,
L.
An
, and
Q.
Huang
, “
Investigation of sol-gel transition in pluronic F127/D2O solutions using a combination of small-angle neutron scattering and monte carlo simulation
,”
J. Phys. Chem. B
110
(
51
),
26424
26429
(
2006
).
53.
Katono
,
H.
,
K.
Sanui
,
N.
Ogata
,
T.
Okano
, and
Y.
Sakurai
, “
Drug release OFF behavior and deswelling kinetics of thermo-responsive ipns composed of poly(acrylamide-co-butyl methacrylate) and poly(acrylic acid)
,”
Polym. J.
23
(
10
),
1179
1189
(
1991
).
54.
Klempner
,
D.
,
L. H.
Sperling
, and
L. A.
Utracki
,
Interpenetrating Polymer Networks
(
American Chemical Society
,
Washington
,
1994
), Vol.
239
.
55.
Berndt
,
I.
,
J. S.
Pedersen
, and
W.
Richtering
, “
Temperature-sensitive core-shell microgel particles with dense shell
,”
Angew. Chem. Int. Ed. Engl.
45
(
11
),
1737
1741
(
2006
).
56.
Kossuth
,
M. B.
,
D. C.
Morse
, and
F. S.
Bates
, “
Viscoelastic behavior of cubic phases in block copolymer melts
,”
J. Rheol.
43
(
1
),
167
196
(
1999
).
57.
Mortensen
,
K.
, “
PEO-related block copolymer surfactants
,”
Colloids Surf. A Physicochem. Eng. Asp.
183–185
,
277
292
(
2001
).
58.
See supplementary material at http://dx.doi.org/10.1122/1.5009202 for more rheological results, e.g., temperature sweep results, Lissajous curves at various concentrations, SFRS and creep results.
59.
Rogers
,
S. A.
,
B. M.
Erwin
,
D.
Vlassopoulos
, and
M.
Cloitre
, “
A sequence of physical processes determined and quantified in LAOS: Application to a yield stress fluid
,”
J. Rheol.
55
(
2
),
435
458
(
2011
).
60.
Rogers
,
S. A.
, “
A sequence of physical processes determined and quantified in LAOS: An instantaneous local 2D/3D approach
,”
J. Rheol.
56
(
5
),
1129
1151
(
2012
).
61.
Denn
,
M. M.
, and
D.
Bonn
, “
Issues in the flow of yield-stress liquids
,”
Rheol. Acta
50
(
4
),
307
315
(
2010
).
62.
Li
,
X.
,
S.-Q.
Wang
, and
X.
Wang
, “
Nonlinearity in large amplitude oscillatory shear (LAOS) of different viscoelastic materials
,”
J. Rheol.
53
(
5
),
1255
1274
(
2009
).
63.
Ozkan
,
S.
,
T. W.
Gillece
,
L.
Senak
, and
D. J.
Moore
, “
Characterization of yield stress and slip behaviour of skin/hair care gels using steady flow and LAOS measurements and their correlation with sensorial attributes
,”
Int. J. Cosmet. Sci.
34
(
2
),
193
201
(
2012
).
64.
Yoshimura
,
A. S.
,
R. K.
Prud'homme
,
H. M.
Princen
, and
A. D.
Kiss
, “
A comparison of techniques for measuring yield stresses
,”
J. Rheol.
31
(
8
),
699
710
(
1987
).
65.
Jalaal
,
M.
,
G.
Cottrell
,
N.
Balmforth
, and
B.
Stoeber
, “
On the rheology of Pluronic F127 aqueous solutions
,”
J. Rheol.
61
(
1
),
139
146
(
2017
).
66.
Wyss
,
H. M.
,
K.
Miyazaki
,
J.
Mattsson
,
Z.
Hu
,
D. R.
Reichman
, and
D. A.
Weitz
, “
Strain-rate frequency superposition: A rheological probe of structural relaxation in soft materials
,”
Phys. Rev. Lett.
98
(
23
),
238303
(
2007
).
67.
Wen
,
Y. H.
,
J. L.
Schaefer
, and
L. A.
Archer
, “
Dynamics and rheology of soft colloidal glasses
,”
ACS Macro Lett.
4
(
1
),
119
123
(
2015
).
68.
Kowalczyk
,
A.
,
B.
Hochstein
,
P.
Stalhle
, and
N.
Willenbacher
, “
Characterization of complex fluids at very low frequency: Experimental verification of the strain rate-frequency superposition (SRFS) method
,”
Appl. Rheol.
20
(
5
),
52340
(
2010
).
69.
Erwin
,
B. M.
,
S. A.
Rogers
,
M.
Cloitre
, and
D.
Vlassopoulos
, “
Examining the validity of strain-rate frequency superposition when measuring the linear viscoelastic properties of soft materials
,”
J. Rheol.
54
(
2
),
187
195
(
2010
).
70.
Bae
,
J.-E.
, and
K. S.
Cho
, “
Logarithmic method for continuous relaxation spectrum and comparison with previous methods
,”
J. Rheol.
59
(
4
),
1081
1112
(
2015
).

Supplementary Material

You do not currently have access to this content.