Nanoconfined poly(4-methylstyrene) [P(4-MS)] films exhibit reductions in glass transition temperature (Tg) relative to bulk Tg (Tg,bulk). Ellipsometry reveals that 15-nm-thick P(4-MS) films supported on silicon exhibit TgTg,bulk = − 15 °C. P(4-MS) films also exhibit fragility-confinement effects; fragility decreases ∼60% in going from bulk to a 20-nm-thick film. Previous research found that incorporating 2–6 mol  % 2-ethylhexyl acrylate (EHA) comonomer in styrene-based random copolymers eliminates Tg- and fragility-confinement effects in polystyrene. Here, we demonstrate that incorporating 3 mol  % EHA in a 4-MS-based random copolymer, 97/3 P(4-MS/EHA), eliminates the Tg- and fragility-confinement effects. The invariance of fragility with nanoconfinement of 97/3 P(4-MS/EHA) films, hypothesized to originate from the interdigitation of ethylhexyl groups, indicates that the presence of EHA prevents the free surface from perturbing chain packing and the cooperative mobility associated with Tg. This method of eliminating confinement effects is advantageous as it relies on the simplest of polymerization methods and neat copolymer only slightly altered in composition from homopolymer. We also investigated whether we could eliminate the Tg-confinement effect with low levels of 2-ethylhexyl methacrylate (EHMA) in 4-MS-based or styrene-based copolymers. Although EHMA is structurally nearly identical to EHA, 4-MS-based and styrene-based copolymers incorporating 4 mol  % EHMA exhibit Tg-confinement effects similar to P(4-MS) and polystyrene. These results support the special character of EHA in eliminating confinement effects originating at free surfaces.

1.
J. A.
Forrest
,
K.
Dalnoki-Veress
, and
J. R.
Dutcher
, “
Interface and chain confinement effects on the glass transition temperature of thin polymer films
,”
Phys. Rev. E
56
,
5705
5716
(
1997
).
2.
C. J.
Ellison
,
M. K.
Mundra
, and
J. M.
Torkelson
, “
Impacts of polystyrene molecular weight and modification to the repeat unit structure on the glass transition–nanoconfinement effect and the cooperativity length scale
,”
Macromolecules
38
,
1767
1778
(
2005
).
3.
R. D.
Priestley
,
C. J.
Ellison
,
L. J.
Broadbelt
, and
J. M.
Torkelson
, “
Structural relaxation of polymer glasses at surfaces, interfaces, and in between
,”
Science
309
,
456
459
(
2005
).
4.
A.
Shavit
and
R. A.
Riggleman
, “
Physical aging, the local dynamics of glass-forming polymers under nanoscale confinement
,”
J. Phys. Chem. B
118
,
9096
9103
(
2014
).
5.
J. M.
Torres
,
C. M.
Stafford
, and
B. D.
Vogt
, “
Elastic modulus of amorphous polymer thin films: Relationship to the glass transition temperature
,”
ACS Nano
3
,
2677
2685
(
2009
).
6.
G.
Wang
,
F.
Najafi
,
K.
Ho
,
M.
Hamidinejad
,
T.
Cui
,
G. C.
Walker
,
C. V.
Singh
, and
T.
Filleter
, “
Mechanical size effect of freestanding nanoconfined polymer films
,”
Macromolecules
55
,
1248
1259
(
2022
).
7.
Y.
Han
,
X.
Huang
,
A. C. W.
Rohrbach
, and
C. B.
Roth
, “
Comparing refractive index and density changes with decreasing film thickness in thin supported films across different polymers
,”
J. Chem. Phys.
153
,
044902
(
2020
).
8.
H. G.
Peng
,
Y. P.
Kong
, and
A. F.
Yee
, “
Relaxation kinetics of nanostructures on polymer surface: Effect of stress, chain mobility, and spatial confinement
,”
Macromolecules
43
,
409
417
(
2010
).
9.
D. B.
Hall
and
J. M.
Torkelson
, “
Small molecule probe diffusion in thin and ultrathin supported polymer films
,”
Macromolecules
31
,
8817
8825
(
1998
).
10.
K.
Paeng
,
S. F.
Swallen
, and
M. D.
Ediger
, “
Direct measurement of molecular motion in freestanding polystyrene thin films
,”
J. Am. Chem. Soc.
133
,
8444
8447
(
2011
).
11.
D.
Richter
and
M.
Kruteva
, “
Polymer dynamics under confinement
,”
Soft Matter
19
,
7316
7349
(
2019
).
12.
K.
Shin
,
S.
Obukhov
,
J.
Chen
,
J.
Huh
,
Y.
Hwang
,
S.
Mok
,
P.
Dobriyal
,
P.
Thiyagarajan
, and
T. P.
Russell
, “
Enhanced mobility of confined polymers
,”
Nat. Mater.
6
,
961
965
(
2007
).
13.
L.
Si
,
M. V.
Massa
,
K.
Dalnoki-Veress
,
H. R.
Brown
, and
R. A. L.
Jones
, “
Chain entanglement in thin freestanding polymer films
,”
Phys. Rev. Lett.
94
,
127801
(
2005
).
14.
S. D.
Kim
and
J. M.
Torkelson
, “
Nanoscale confinement and temperature effects on associative polymers in thin films: Fluorescence study of a telechelic, pyrene-labeled poly(dimethylsiloxane)
,”
Macromolecules
35
,
5943
5952
(
2002
).
15.
B.
Chen
and
J. M.
Torkelson
, “
Development of rigid amorphous fraction in cold-crystallized syndiotactic polystyrene films confined near the nanoscale: Novel analysis via ellipsometry
,”
J. Polym. Sci.
60
,
1631
1642
(
2022
).
16.
J. L.
Keddie
,
R. A. L.
Jones
, and
R. A.
Cory
, “
Size-dependent depression of the glass transition temperature in polymer films
,”
Europhys. Lett.
27
,
59
64
(
1994
).
17.
J. L.
Keddie
,
R. A. L.
Jones
, and
R. A.
Cory
, “
Interface and surface effects on the glass-transition temperature in thin polymer films
,”
Faraday Discuss.
98
,
219
230
(
1994
).
18.
J. H.
van Zanten
,
W. E.
Wallace
, and
W. L.
Wu
, “
Effect of strongly favorable substrate interactions on the thermal properties of ultrathin polymer films
,”
Phys. Rev. E
53
,
R2053
(
1996
).
19.
J. H.
Kim
,
J.
Jang
, and
W. C.
Zin
, “
Estimation of the thickness dependence of the glass transition temperature in various thin polymer films
,”
Langmuir
16
,
4064
4067
(
2000
).
20.
K.
Dalnoki-Veress
,
J. A.
Forrest
,
C.
Murray
,
C.
Gigault
, and
J. R.
Dutcher
, “
Molecular weight dependence of reductions in the glass transition temperature of thin, freely standing polymer films
,”
Phys. Rev. E
63
,
031801
(
2001
).
21.
C. J.
Ellison
and
J. M.
Torkelson
, “
The distribution of glass-transition temperatures in nanoscopically confined glass formers
,”
Nat. Mater.
2
,
695
700
(
2003
).
22.
C. M.
Evans
,
H.
Deng
,
W. F.
Jager
, and
J. M.
Torkelson
, “
Fragility is a key parameter in determining the magnitude of Tg-confinement effects in polymer films
,”
Macromolecules
46
,
6091
6103
(
2013
).
23.
T.
Lan
and
J. M.
Torkelson
, “
Fragility-confinement effects: Apparent universality as a function of scaled thickness in films of freely deposited, linear polymer and its absence in densely grafted brushes
,”
Macromolecules
49
,
1331
1343
(
2016
).
24.
R. D.
Priestley
,
D.
Cangialosi
, and
S.
Napolitano
, “
On the equivalence between the thermodynamic and dynamic measurements of the glass transition in confined polymers
,”
J. Non-Cryst. Solids
407
,
288
295
(
2015
).
25.
K.
Geng
and
O. K. C.
Tsui
, “
Effects of polymer tacticity and molecular weight on the glass transition temperature of poly(methyl methacrylate) films on silica
,”
Macromolecules
49
,
2671
2678
(
2016
).
26.
D.
Liu
,
H.
Qin
,
J.
Zhang
, and
T.
Wang
, “
Thickness-dependent glass transition temperature and charge mobility in cross-linked polyfluorene thin films
,”
Phys. Rev. E
94
,
052503
(
2016
).
27.
T.
Wang
,
S.
Hu
,
S.
Zhang
,
A.
Peera
,
J.
Reffner
, and
J. M.
Torkelson
, “
Eliminating the Tg-confinement effect in polystyrene films: Extraordinary impact of a 2 mol % 2-ethylhexyl acrylate comonomer
,”
Macromolecules
55
,
9601
9611
(
2022
).
28.
T.
Wang
,
A.
Peera
,
J.
Reffner
, and
J. M.
Torkelson
, “
Reducing the bulk fragility and suppressing the fragility-confinement effect in polystyrene with very low levels of 2-ethylhexyl acrylate comonomer
,”
Macromolecules
56
,
3527
3537
(
2023
).
29.
K.
Jin
and
J. M.
Torkelson
, “
Enhanced Tg-confinement effect in cross-linked polystyrene compared to its linear precursor: Roles of fragility and chain architecture
,”
Macromolecules
49
,
5092
5103
(
2016
).
30.
K.
Fukao
and
Y.
Miyamoto
, “
Glass transitions and dynamics in thin polymer films: Dielectric relaxation of thin films of polystyrene
,”
Phys. Rev. E
61
,
1743
1754
(
2000
).
31.
O. K. C.
Tsui
and
H. F.
Zhang
, “
Effects of chain ends and chain entanglement on the glass transition temperature of polymer thin films
,”
Macromolecules
34
,
9139
9142
(
2001
).
32.
F.
Xie
,
H. F.
Zhang
,
F. K.
Lee
,
B.
Du
,
O. K. C.
Tsui
,
Y.
Yokoe
,
K.
Tanaka
,
A.
Takahara
,
T.
Kajiyama
, and
T.
He
, “
Effect of low surface energy chain ends on the glass transition temperature of polymer thin films
,”
Macromolecules
35
,
1491
1492
(
2002
).
33.
J. S.
Sharp
and
J. A.
Forrest
, “
Free surfaces cause reductions in the glass transition temperature of thin polystyrene films
,”
Phys. Rev. Lett.
91
,
235701
(
2003
).
34.
Z.
Fakhraai
and
J. A.
Forrest
, “
Probing slow dynamics in supported thin polymer films
,”
Phys. Rev. Lett.
95
,
025701
(
2005
).
35.
C. B.
Roth
,
A.
Pound
,
S. W.
Kamp
,
C. A.
Murray
, and
J. R.
Dutcher
, “
Molecular-weight dependence of the glass transition temperature of freely-standing poly(methyl methacrylate) films
,”
Eur. Phys. J. E
20
,
441
448
(
2006
).
36.
C. B.
Roth
,
K. L.
McNerny
,
W. F.
Jager
, and
J. M.
Torkelson
, “
Eliminating the enhanced mobility at the free surface of polystyrene: Fluorescence studies of the glass transition temperature in thin bilayer films of immiscible polymers
,”
Macromolecules
40
,
2568
2574
(
2007
).
37.
S.
Kim
,
S. A.
Hewlett
,
C. B.
Roth
, and
J. M.
Torkelson
, “
Confinement effects on glass transition temperature, transition breadth, and expansivity: Comparison of ellipsometry and fluorescence measurements on polystyrene films
,”
Eur. Phys. J. E
30
,
83
92
(
2009
).
38.
R.
Inoue
,
K.
Kawashima
,
K.
Matsui
,
T.
Kanaya
,
K.
Nishida
,
G.
Matsuba
, and
M.
Hino
, “
Distributions of glass-transition temperature and thermal expansivity in multilayered polystyrene thin films studied by neutron reflectivity
,”
Phys. Rev. E
83
,
021801
(
2011
).
39.
S.
Kim
and
J. M.
Torkelson
, “
Distribution of glass transition temperatures in free-standing, nanoconfined polystyrene films: A test of de Gennes’ sliding motion mechanism
,”
Macromolecules
44
,
4546
4553
(
2011
).
40.
S.
Gao
,
Y. P.
Koh
, and
S. L.
Simon
, “
Calorimetric glass transition of single polystyrene ultrathin films
,”
Macromolecules
46
,
562
570
(
2013
).
41.
M. K.
Mundra
,
S. K.
Donthu
,
V. P.
Dravid
, and
J. M.
Torkelson
, “
Effect of spatial confinement on the glass-transition temperature of patterned polymer nanostructures
,”
Nano Lett.
7
,
713
718
(
2007
).
42.
B.
Li
,
X.
Lu
,
Y.
Ma
,
X.
Han
, and
Z.
Chen
, “
Method to probe glass transition temperatures of polymer thin films
,”
ACS Macro Lett.
4
,
548
551
(
2015
).
43.
D.
Kawaguchi
,
Y.
Tateishi
, and
K.
Tanaka
, “
Time-resolved fluorescence analysis for dye-labeled polystyrene in thin films
,”
J. Non-Cryst. Solids
407
,
284
287
(
2015
).
44.
R. R.
Baglay
and
C. B.
Roth
, “
Communication: Experimentally determined profile of local glass transition temperature across a glassy-rubbery polymer interface with a Tg difference of 80 K
,”
J. Chem. Phys.
143
,
111101
(
2015
).
45.
T.
Chang
,
H.
Zhang
,
X.
Shen
, and
Z.
Hu
, “
Polymer–polymer interfacial perturbation on the glass transition of supported low molecular weight polystyrene thin films
,”
ACS Macro Lett.
8
,
435
441
(
2019
).
46.
T.
Wang
,
J.
Yan
,
H.
Yuan
,
J.
Xu
,
H. Y.
Lam
,
X.
Yu
,
C.
Lv
,
B.
Du
, and
O. K. C.
Tsui
, “
Tg confinement effect of random copolymers of 4-tert-butylstyrene and 4-acetoxystyrene with different compositions
,”
ACS Macro Lett.
8
,
1280
1284
(
2019
).
47.
G.
Vignaud
,
M. S.
Chebil
,
J. K.
Bal
,
N.
Delorme
,
T.
Beuvier
,
Y.
Grohens
, and
A.
Gibaud
, “
Densification and depression in glass transition temperature in polystyrene thin films
,”
Langmuir
30
,
11599
11608
(
2014
).
48.
J.
Mattsson
,
J. A.
Forrest
, and
L.
Borjesson
, “
Quantifying glass transition behavior in ultrathin free-standing polymer films
,”
Phys. Rev. E
62
,
5187
5200
(
2000
).
49.
K.
Geng
,
F.
Chen
, and
O. K. C.
Tsui
, “
Molecular-weight dependent Tg depression of silica-supported poly(α-methyl styrene) films
,”
J. Non-Cryst. Solids
407
,
296
301
(
2015
).
50.
Q.
Xu
,
N.
Zhu
,
H.
Fang
,
X.
Wang
,
R. D.
Priestley
, and
B.
Zuo
, “
Decoupling role of film thickness and interfacial effect on polymer thin film dynamics
,”
ACS Macro Lett.
10
,
1
8
(
2021
).
51.
Z.
Hao
,
A.
Ghanekarade
,
N.
Zhu
,
K.
Randazzo
,
D.
Kawaguchi
,
K.
Tanaka
,
X.
Wang
,
D. S.
Simmons
,
R. D.
Priestley
, and
B.
Zuo
, “
Mobility gradients yield rubbery surfaces on top of polymer glasses
,”
Nature
596
,
372
376
(
2021
).
52.
C. J.
Ellison
,
R. L.
Ruszkowski
,
N. J.
Fredin
, and
J. M.
Torkelson
, “
Dramatic reduction of the effect of nanoconfinement on the glass transition of polymer films via addition of small-molecule diluent
,”
Phys. Rev. Lett.
92
,
095702
(
2004
).
53.
M. K.
Mundra
,
C. J.
Ellison
,
P.
Rittigstein
, and
J. M.
Torkelson
, “
Fluorescence studies of confinement in polymer films and nanocomposites: Glass transition temperature, plasticizer effects, and sensitivity to stress relaxation and local polarity
,”
Eur. Phys. J.: Spec. Top.
141
,
143
151
(
2007
).
54.
S.
Kim
,
M. K.
Mundra
,
C. B.
Roth
, and
J. M.
Torkelson
, “
Suppression of the Tg-nanoconfinement effect in thin poly(vinyl acetate) films by sorbed water
,”
Macromolecules
43
,
5158
5161
(
2010
).
55.
L.
Zhang
and
J. M.
Torkelson
, “
Influence of initiator fragments as chain ends on the Tg-confinement effect and dewetting of thin films of ultralow molecular weight polymer
,”
Polymer
65
,
105
114
(
2015
).
56.
L.
Chen
and
J. M.
Torkelson
, “
Tuning the Tg-confinement effect in thin polymer films via minute levels of residual surfactant which ‘cap’ the free surface
,”
Polymer
87
,
226
235
(
2016
).
57.
E.
Glynos
,
B.
Frieberg
,
H.
Oh
,
M.
Liu
,
D. W.
Gidley
, and
P. F.
Green
, “
Role of molecular architecture on the vitrification of polymer thin films
,”
Phys. Rev. Lett.
106
,
128301
(
2011
).
58.
T.
Lan
and
J. M.
Torkelson
, “
Substantial spatial heterogeneity and tunability of glass transition temperature observed with dense polymer brushes prepared by ARGET ATRP
,”
Polymer
64
,
183
(
2015
).
59.
L.
Zhang
,
R.
Elupula
,
S. M.
Grayson
, and
J. M.
Torkelson
, “
Major impact of cyclic chain topology on the Tg-confinement effect of supported thin films of polystyrene
,”
Macromolecules
49
,
257
268
(
2016
).
60.
L.
Zhang
,
R.
Elupula
,
S. M.
Grayson
, and
J. M.
Torkelson
, “
Suppression of the fragility-confinement effect via low molecular weight cyclic or ring polymer topology
,”
Macromolecules
50
,
1147
1154
(
2017
).
61.
L.
Li
,
Z.
Qiang
,
X.
Chen
,
K.
Jin
,
M.
Wang
, and
J. M.
Torkelson
, “
Impact of bottlebrush chain architecture on Tg-confinement and fragility-confinement effects enabled by thermo-cleavable bottlebrush polymers synthesized by radical coupling and atom transfer radical polymerization
,”
J. Polym. Sci.
58
,
2887
2905
(
2020
).
62.
H.
Zhang
,
T.
Chang
,
S.
Zhang
,
K.
Zhou
,
W.
Zhang
, and
Z.
Hu
, “
Effects of chain ends and densities on the glass transition of polymer thin films probed by linear and cyclic polystyrene
,”
Polymer
253
,
124986
(
2022
).
63.
C. G.
Campbell
and
B. D.
Vogt
, “
Examination of the influence of cooperative segmental dynamics on the glass transition and coefficient of thermal expansion in thin films probed using poly(n-alkyl methacrylate)s
,”
Polymer
48
,
7169
7175
(
2007
).
64.
E. C.
Glor
,
R. J.
Composto
, and
Z.
Fakhraai
, “
Glass transition dynamics and fragility of ultrathin miscible polymer blend films
,”
Macromolecules
48
,
6682
6689
(
2015
).
65.
K.
Jin
and
J. M.
Torkelson
, “
Tg-confinement effects in strongly miscible blends of poly(2,6-dimethyl-1,4-phenylene oxide) and polystyrene: Roles of bulk fragility and chain segregation
,”
Polymer
118
,
85
96
(
2017
).
66.
C. H.
Park
,
J. H.
Kim
,
M.
Ree
,
B.
Sohn
,
J. C.
Jung
, and
W.
Zin
, “
Thickness and composition dependence of the glass transition temperature in thin random copolymer films
,”
Polymer
45
,
4507
4513
(
2004
).
67.
S.
Kawana
and
R. A. L.
Jones
, “
Character of the glass transition in thin supported polymer films
,”
Phys. Rev. E
63
,
021501
(
2001
).
68.
M. K.
Mundra
,
C. J.
Ellison
,
R. E.
Behling
, and
J. M.
Torkelson
, “
Confinement, composition, and spin-coating effects on the glass transition and stress relaxation of thin films of polystyrene and styrene-containing random copolymers: Sensing by intrinsic fluorescence
,”
Polymer
47
,
7747
7759
(
2006
).
69.
S.
Askar
,
L.
Li
, and
J. M.
Torkelson
, “
Polystyrene-grafted silica nanoparticles: Investigating the molecular weight dependence of glass transition and fragility behavior
,”
Macromolecules
50
,
1589
1598
(
2017
).
70.
S.
Askar
,
T.
Wei
,
A. W.
Tan
, and
J. M.
Torkelson
, “
Molecular weight dependence of the intrinsic size effect on Tg in AAO template-supported polymer nanorods: A DSC study
,”
J. Chem. Phys.
146
,
203323
(
2017
).
71.
O.
Baumchen
,
J. D.
McGraw
,
J. A.
Forrest
, and
K.
Dalnoki-Veress
, “
Reduced glass transition temperatures in thin polymer films: Surface effect or artifact?
,”
Phys. Rev. Lett.
109
,
055701
(
2012
).
72.
C.
Zhang
,
V. M.
Boucher
,
D.
Cangialosi
, and
R. D.
Priestley
, “
Mobility and glass transition temperature of polymer nanospheres
,”
Polymer
54
,
230
235
(
2013
).
73.
T.
Kanaya
,
H.
Ogawa
,
M.
Kishimoto
,
R.
Inoue
,
A.
Suter
, and
T.
Prokscha
, “
Distribution of glass transition temperatures Tg in polystyrene thin films as revealed by low-energy muon spin relaxation: A comparison with neutron reflectivity results
,”
Phys. Rev. E
92
,
022604
(
2015
).
74.
W.
Ren
,
X.
Wang
,
J.
Shi
,
J.
Xu
,
H.
Taneda
,
N. L.
Yamada
,
D.
Kawaguchi
,
K.
Tanaka
, and
X.
Wang
, “
The role of the molecular weight of the adsorbed layer on a substrate in the suppressed dynamics of supported thin polystyrene films
,”
Soft Matter
18
,
1997
2005
(
2022
).
75.
T.
Wei
and
J. M.
Torkelson
, “
Molecular weight dependence of the glass transition temperature (Tg)-confinement effect in well-dispersed poly(2-vinyl pyridine)–silica nanocomposites: Comparison of interfacial layer Tg and matrix Tg
,”
Macromolecules
53
,
8725
8736
(
2020
).
76.
K. S.
Schweizer
and
D. S.
Simmons
, “
Progress towards a phenomenological picture and theoretical understanding of glassy dynamics and vitrification near interfaces and under nanoconfinement
,”
J. Chem. Phys.
151
,
240901
(
2019
).
77.
G.
Strobl
,
The Physics of Polymers: Concepts for Understanding Their Structures and Behavior
, 3rd ed. (
Springer
,
2007
).
78.
J.
Xu
,
S.
Wang
,
G. J. N.
Wang
,
C.
Zhu
,
S.
Luo
,
L.
Jin
,
X.
Gu
,
S.
Chen
,
V. R.
Feig
,
J. W. F.
To
,
S.
Rondeau-Gagne
,
J.
Park
,
B. C.
Schroeder
,
C.
Lu
,
J. Y.
Oh
,
Y.
Wang
,
Y.
Kim
,
H.
Yan
,
R.
Sinclair
,
D.
Zhou
,
G.
Xue
,
B.
Murmann
,
C.
Linder
,
W.
Cai
,
J. B. H.
Tok
,
J. W.
Chung
, and
Z.
Bao
, “
Highly stretchable polymer semiconductor films through the nanoconfinement effect
,”
Science
355
,
59
64
(
2017
).
79.
P.
Podsiadlo
,
A. K.
Kaushik
,
E. M.
Arruda
,
A. M.
Waas
,
B. S.
Shim
,
J.
Xu
,
H.
Nandivada
,
B. G.
Pumplin
,
J.
Lahann
,
A.
Ramamoorthy
, and
N. A.
Kotov
, “
Ultrastrong and stiff layered polymer nanocomposites
,”
Science
318
,
80
83
(
2007
).
80.
J. Y.
Oh
,
D.
Son
,
T.
Katsumata
,
Y.
Lee
,
Y.
Kim
,
J.
Lopez
,
H.
Wu
,
J.
Kang
,
J.
Park
,
X.
Gu
,
J.
Mun
,
N. G.
Wang
,
Y.
Yin
,
W.
Cai
,
Y.
Yun
,
J. B. H.
Tok
, and
Z.
Bao
, “
Stretchable self-healable semiconducting polymer film for active-matrix strain-sensing array
,”
Sci. Adv.
5
,
eeav3097
(
2019
).
81.
M. J.
Burroughs
,
S.
Napolitano
,
D.
Cangialosi
, and
R. D.
Priestley
, “
Direct measurement of glass transition temperature in exposed and buried adsorbed polymer nanolayers
,”
Macromolecules
49
,
4647
4655
(
2016
).
82.
C. M.
Bates
,
M. J.
Maher
,
D. W.
Janes
,
C. J.
Ellison
, and
C. G.
Willson
, “
Block copolymer lithography
,”
Macromolecules
47
,
2
12
(
2014
).
83.
C. G.
Hardy
and
C.
Tang
, “
Advances in square arrays through self-assembly and directed self-assembly of block copolymers
,”
J. Polym. Sci., Part B: Polym. Phys.
51
,
2
15
(
2013
).
84.
S. Y.
Yang
,
J.
Yang
,
E.
Kim
,
G.
Jeon
,
E. J.
Oh
,
Y.
Choi
,
S. K.
Hahn
, and
J. K.
Kim
, “
Single-file diffusion of protein drugs through cylindrical nanochannels
,”
ACS Nano
4
,
3817
3822
(
2010
).
85.
C. A.
Angell
, “
Spectroscopy simulation and scattering, and the medium range order problem in glass
,”
J. Non-Cryst. Solids
73
,
1
17
(
1985
).
86.
L. M.
Wang
,
V.
Velikov
, and
C. A.
Angell
, “
Direct determination of kinetic fragility indices of glassforming liquids by differential scanning calorimetry: Kinetic versus thermodynamic fragilities
,”
J. Chem. Phys.
117
,
10184
10192
(
2002
).
87.
R. P.
White
,
D.
Buculei
,
A. M. J. M.
Beale
,
I.
Goovaerts
,
J. L.
Keddie
, and
J. E. G.
Lipson
, “
Spectroscopic ellipsometry as a route to thermodynamic characterization
,”
Soft Matter
18
,
6660
6673
(
2022
).
88.
J. E. G.
Lipson
and
S. T.
Milner
, “
Local and average glass transitions in polymer thin films
,”
Macromolecules
43
,
9874
9880
(
2010
).
89.
C.
Dalle-Ferrier
,
S.
Simon
,
W.
Zheng
,
P.
Badrinarayanan
,
T.
Fennell
,
B.
Frick
,
J. M.
Zanotti
, and
C.
Alba-Simionesco
, “
Consequence of excess configurational entropy on fragility: The case of a polymer-oligomer blend
,”
Phys. Rev. Lett.
103
,
185702
(
2009
).
90.
Q.
Wang
,
L.
Kang
,
X.
Xu
,
M.
Zhang
,
A.
Chao
,
J.
Chen
,
Z.
Han
,
H.
Yu
,
R.
Li
,
Y.
Zhao
,
D.
Zhang
, and
N.
Jiang
, “
Multiscale crystalline structure of confined polypeptoid films: The effect of alkyl side chain branching
,”
ACS Macro Lett.
11
,
1060
1066
(
2022
).
91.
J.
Brandrup
,
E. H.
Immergut
,
E. A.
Grulke
,
A.
Abe
, and
D. R.
Block
,
Polymer Handbook
(
Wiley
,
New York
,
1999
).

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