We have studied the liquid-like response of the surface of vapor-deposited glassy films of polystyrene to the introduction of gold nanoparticles on the surface. The build-up of polymer material was measured as a function of time and temperature for both as-deposited films, as well as films that have been rejuvenated to become normal glasses cooled from the equilibrium liquid. The temporal evolution of the surface profile is well described by the characteristic power law of capillary-driven surface flows. In all cases, the surface evolution of the as-deposited films and the rejuvenated films is enhanced compared to bulk and is not easily distinguishable from each other. The temperature dependence of the measured relaxation times determined from the surface evolution is found to be quantitatively comparable to similar studies for high molecular weight spincast polystyrene. Comparisons to numerical solutions of the glassy thin film equation provide quantitative estimates of the surface mobility. For temperatures sufficiently close to the glass-transition temperature, particle embedding is also measured and used as a probe of bulk dynamics, and, in particular, bulk viscosity.

1.
H.
Tian
,
Q.
Xu
,
H.
Zhang
,
R. D.
Priestley
, and
B.
Zuo
, “
Surface dynamics of glasses
,”
Appl. Phys. Rev.
9
,
011316
(
2022
).
2.
L.
Berthier
,
P.
Charbonneau
,
E.
Flenner
, and
F.
Zamponi
, “
Origin of ultrastability in vapor-deposited glasses
,”
Phys. Rev. Lett.
119
,
188002
(
2017
).
3.
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
).
4.
J. A.
Forrest
and
K.
Dalnoki-Veress
, “
When does a glass transition temperature not signify a glass transition?
,”
ACS Macro Lett.
3
,
310
314
(
2014
).
5.
M. D.
Ediger
and
J. A.
Forrest
, “
Dynamics near free surfaces and the glass transition in thin polymer films: A view to the future
,”
Macromolecules
47
,
471
478
(
2014
).
6.
Z.
Yang
,
Y.
Fujii
,
F. K.
Lee
,
C.-H.
Lam
, and
O. K. C.
Tsui
, “
Glass transition dynamics and surface layer mobility in unentangled polystyrene films
,”
Science
328
,
1676
1679
(
2010
).
7.
S. F.
Swallen
 et al, “
Organic glasses with exceptional thermodynamic and kinetic stability
,”
Science
315
,
353
356
(
2007
).
8.
P.
Luo
 et al, “
Ultrastable metallic glasses formed on cold substrates
,”
Nat. Commun.
9
,
1389
(
2018
).
9.
A. N.
Raegen
,
J.
Yin
,
Q.
Zhou
, and
J. A.
Forrest
, “
Ultrastable monodisperse polymer glass formed by physical vapour deposition
,”
Nat. Mater.
19
,
1110
1113
(
2020
).
10.
S. L. L. M.
Ramos
,
M.
Oguni
,
K.
Ishii
, and
H.
Nakayama
, “
Character of devitrification, viewed from enthalpic paths, of the vapor-deposited ethylbenzene glasses
,”
J. Phys. Chem. B
115
,
14327
14332
(
2011
).
11.
E.
Leon-Gutierrez
,
A.
Sepúlveda
,
G.
Garcia
,
M. T.
Clavaguera-Mora
, and
J.
Rodríguez-Viejo
, “
Stability of thin film glasses of toluene and ethylbenzene formed by vapor deposition: An in situ nanocalorimetric study
,”
Phys. Chem. Chem. Phys.
12
,
14693
14698
(
2010
).
12.
E.
Leon-Gutierrez
,
A.
Sepúlveda
,
G.
Garcia
,
M. T.
Clavaguera-Mora
, and
J.
Rodríguez-Viejo
, “
Correction: Stability of thin film glasses of toluene and ethylbenzene formed by vapor deposition: An in situ nanocalorimetric study
,”
Phys. Chem. Chem. Phys.
18
,
8244
8245
(
2016
).
13.
J. H.
Teichroeb
and
J. A.
Forrest
, “
Direct imaging of nanoparticle embedding to probe viscoelasticity of polymer surfaces
,”
Phys. Rev. Lett.
91
,
016104
(
2003
).
14.
J. S.
Sharp
,
J. H.
Teichroeb
, and
J. A.
Forrest
, “
The properties of free polymer surfaces and their influence on the glass transition temperature of thin polystyrene films
,”
Eur. Phys. J. E
15
,
473
487
(
2004
).
15.
S. A.
Hutcheson
and
G. B.
McKenna
, “
Nanosphere embedding into polymer surfaces: A viscoelastic contact mechanics analysis
,”
Phys. Rev. Lett.
94
,
076103
(
2005
).
16.
D.
Qi
,
C. R.
Daley
,
Y.
Chai
, and
J. A.
Forrest
, “
Molecular weight dependence of near surface dynamical mechanical properties of polymers
,”
Soft Matter
9
,
8958
8964
(
2013
).
17.
C. R.
Daley
,
Z.
Fakhraai
,
M. D.
Ediger
, and
J. A.
Forrest
, “
Comparing surface and bulk flow of a molecular glass former
,”
Soft Matter
8
,
2206
2212
(
2012
).
18.
R. D.
Deshmukh
and
R. J.
Composto
, “
Direct observation of nanoparticle embedding into the surface of a polymer melt
,”
Langmuir
23
,
13169
13173
(
2007
).
19.
Z.
Fakhraai
and
J. A.
Forrest
, “
Measuring the surface dynamics of glassy polymers
,”
Science
319
,
600
604
(
2008
).
20.
Y.
Chai
 et al, “
A direct quantitative measure of surface mobility in a glassy polymer
,”
Science
343
,
994
999
(
2014
).
21.
Y.
Zhang
,
R.
Potter
,
W.
Zhang
, and
Z.
Fakhraai
, “
Using tobacco mosaic virus to probe enhanced surface diffusion of molecular glasses
,”
Soft Matter
12
,
9115
9120
(
2016
).
22.
Y.
Zhang
and
Z.
Fakhraai
, “
Invariant fast diffusion on the surfaces of ultrastable and aged molecular glasses
,”
Phys. Rev. Lett.
118
,
066101
(
2017
).
23.
Y.
Zhang
and
Z.
Fakhraai
, “
Decoupling of surface diffusion and relaxation dynamics of molecular glasses
,”
Proc. Natl. Acad. Sci. U. S. A.
114
,
4915
4919
(
2017
).
24.
S.
Ren
,
C.
Pedersen
,
A.
Carlson
,
T.
Salez
, and
Y.
Wang
, “
Capillary deformation of ultrathin glassy polymer films by air nanobubbles
,”
Phys. Rev. Res.
2
,
043166
(
2020
).
25.
S.
Zhu
,
Y.
Chai
, and
J. A.
Forrest
, “
Evaporative purification to produce highly monodisperse polymers: Application to polystyrene for n = 3–13 and quantification of Tg from oligomer to polymer
,”
Phys. Rev. Mater.
1
,
025605
(
2017
).
26.
J.
Turkevich
,
P. C.
Stevenson
, and
J.
Hillier
, “
A study of the nucleation and growth processes in the synthesis of colloidal gold
,”
Discuss. Faraday Soc.
11
,
55
75
(
1951
).
27.
G. K.
Batchelor
,
An Introduction to Fluid Dynamics
(
Cambridge University Press
,
1967
).
28.
A.
Oron
,
S. H.
Davis
, and
S. G.
Bankoff
, “
Long-scale evolution of thin liquid films
,”
Rev. Mod. Phys.
69
,
931
(
1997
).
29.
J.
Eggers
, “
Contact line motion for partially wetting fluids
,”
Phys. Rev. E
72
,
061605
(
2005
).
30.
S.
Poulain
,
A.
Carlson
,
S.
Mandre
, and
L.
Mahadevan
, “
Elastohydrodynamics of contact in adherent sheets
,”
J. Fluid Mech.
947
,
A16
(
2022
).
31.
C.
Pedersen
,
S.
Ren
,
Y.
Wang
,
A.
Carlson
, and
T.
Salez
, “
Nanobubble-induced flow of immersed glassy polymer films
,”
Phys. Rev. Fluids
6
,
114006
(
2021
).
32.
T.
Salez
,
J. D.
McGraw
,
O.
Bäumchen
,
K.
Dalnoki-Veress
, and
E.
Raphaël
, “
Capillary-driven flow induced by a stepped perturbation atop a viscous film
,”
Phys. Fluids
24
,
102111
(
2012
).
33.
L.
Zhu
 et al, “
Surface self-diffusion of an organic glass
,”
Phys. Rev. Lett.
106
,
256103
(
2011
).
34.
R.
Malshe
,
M. D.
Ediger
,
L.
Yu
, and
J. J.
De Pablo
, “
Evolution of glassy gratings with variable aspect ratios under surface diffusion
,”
J. Chem. Phys.
134
,
194704
(
2011
).
35.
C. R.
Cao
,
Y. M.
Lu
,
H. Y.
Bai
, and
W. H.
Wang
, “
High surface mobility and fast surface enhanced crystallization of metallic glass
,”
Appl. Phys. Lett.
107
,
141606
(
2015
).
36.
Y.
Chai
,
T.
Salez
, and
J. A.
Forrest
, “
Using Mw dependence of surface dynamics of glassy polymers to probe the length scale of free-surface mobility
,”
Macromolecules
53
,
1084
1089
(
2020
).
37.
D.
Qi
, “
On near-free-surface dynamics of thin polymer films
,” Ph.D. thesis (
University of Waterloo
,
2009
).
38.
A.
Dhinojwala
,
G. K.
Wong
, and
J. M.
Torkelson
, “
Rotational reorientation dynamics of disperse red 1 in polystyrene: α-relaxation dynamics probed by second harmonic generation and dielectric relaxation
,”
J. Chem. Phys.
100
,
6046
6054
(
1994
).
39.
W.
Zhang
and
L.
Yu
, “
Surface diffusion of polymer glasses
,”
Macromolecules
49
,
731
735
(
2016
).
40.
T.
Salez
,
J.
Salez
,
K.
Dalnoki-Veress
,
E.
Raphaël
, and
J. A.
Forrest
, “
Cooperative strings and glassy interfaces
,”
Proc. Natl. Acad. Sci. U. S. A.
112
,
8227
8231
(
2015
).
41.
A.
Panagopoulou
and
S.
Napolitano
, “
Irreversible adsorption governs the equilibration of thin polymer films
,”
Phys. Rev. Lett.
119
,
097801
(
2017
).
42.
D.
Qi
,
Z.
Fakhraai
, and
J. A.
Forrest
, “
Substrate and chain size dependence of near surface dynamics of glassy polymers
,”
Phys. Rev. Lett.
101
,
096101
(
2008
).

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