of 31
Supplementary Materials for
Photonic Crystals Formed Through Rapid Self
-
Assembly of Brush Block
Copolymers
Benjamin R. Sveinbjornsson
,
Raymond
A.
Weitekamp
,
Garret M. M
i
yake, Yan Xia, Harry
A.
Atwater, Robert H. Grubbs
*
correspondence to:
rhg@caltech.edu
This PDF file includes:
Materials and Methods
Table
S1
Supplementary Text
Matlab Code
Figs. S1 to S29
References
Supporting Online Material
Photonic Crystals Formed Through Rapid Self
-
Assembly of
Brush Block
Copolymers
Benjamin R. Sveinbjornsson
,
Raymond
A.
Weitekamp
,
Garret M. M
i
yake, Yan Xia, Harry
A.
Atwater, Robert H. Grubbs
*
* To whom correspondence should be addressed at e
-
mail:
rhg@caltech.edu
Materials and Methods
1
. Materials
(H
2
IMes)(pyr)
2
(Cl)
2
RuCHPh
(33)
and
N
-
(hydroxyethanyl)
-
cis
-
5
-
norbornene
-
exo
-
2,3
-
di
-
carboximide
(
1
)
(34)
,
were prepared as described previously.
All solvents were purchased from
VWR
or
Sigma
-
Aldrich.
Ruthenium tetroxide was purchased form Acros Organics.
Ruthenium
-
based metathesis catalyst w
as obtained from Materia Inc
.
and
stored in a drybox. Other
chemicals were bought from Sigma
-
Aldrich. Dry solvents were purified by passing them through
solvent pur
ification columns.
3,6
-
dimethyl
-
1,4
-
dioxane
-
2,5
-
dione
was purified by sublimation
under vacuum. All other solvents and chemicals were used without further purification unless
otherwise stated.
2
.
General information
NMR spectra were recorded
at room tempe
rature
on a Varian Inova 500 (at 500 MHz). The
NMR spectra were analyzed on MestReNova software and are reported relative to CDCl
3
(
δ
7.26). NMR abbreviations:
s = singlet, d = doublet, t = triplet, m = mul
tiplet, br broad, dt
=
doublet of
tri
blets. Gel permeation chromatography (GPC) was carried out in THF on two Plgel
10
μ
m mixed
-
B LS columns (Polymer Laboratories) connected in series with a miniDAWN
TREOS multiangle laser light scattering (MALLS) detector, a ViscoStar viscometer and Optilab
rex differential refractometer (all from Wyatt Technology
.
The d
n
/dc values used
for the
polylactide and polysty
rene macromonomers were 0.050 and 0.180 respectively.
d
n
/dc values
for
the brush block copolymers
were obtained for each injection by assuming 1
00% mass elution
from the columns.
High resolution mass spectra were provided by the California Institute of
Technology Mass spectrometry Facility.
SEM images were taken
on a ZEISS 1550 VP Field
Emission SEM
.
Ellipsometry was performed on a
Sentech SE
-
850
.
Reflection measurements
were performed on a Cary 5000 UV/Vis/NIR spectrophotometer, equipped with an ‘integrating
sphere’ diffuse reflectance accessory (Internal DRA 1800). All measurements were referenced to
a
LabSphere
Spectralon
99%
certified
reflecta
nce standard.
The samples were illuminated
through a Spectralon
-
coated aperature with a diameter of 1 cm, with a beam area of
approximately 0.5 cm
2
. The samples were scanned at a rate of 600 nm/min, with a 1 nm data
interval, from 1800 to 200 nm, with a de
tector crossover (InGaAs to PMT) at 800 nm.
3. Synthesis
N
-
(2
-
bromo
-
2
-
methylpropanoylethanyl)
-
cis
-
5
-
norbornene
-
exo
-
2,3
-
dicarboximide
(2)
A round bottom flask fitted with an addition funnel was flame
-
dried and subsequently charged
with
1
(2.51 g, 12.1
mmol) and triethylamine (2.3 mL, 16 mmol). Dry dichloromethane (80 mL)
was added to the addition funnel and approximately half of it
was
added to the reaction mixture.
To the addition funnel was added 2
-
bromoisobutyrylbromide (2.2 mL 18
mmol). The reaction
flask was submerged in an ice
-
water bath and the mixture in the addition funnel added to the
reaction flask drop wise. When the addition was completed the reaction mixture was allowed to
stir at room temperature for 20 hours. The reaction mixture was wash
ed with 0.1 N HCl (25 mL),
NaHCO
3
(25 mL) and brine (2x 25 mL) and then dried over MgSO
4
and concentrated in vacuo.
The product was purified by silica gel chromatography (dichloromethane) to give the product as
a white solid in 66 % yield (2.87 g, 8.0 mmol
).
1
H NMR (500 MHz, CDCl
3
):
δ
(ppm)
6.28
(t,
J
=
1.8 Hz, 2H), 4.34
-
4.32 (m, 2H), 3.82
-
3.80 (m, 2H), 3.28
-
3.26
(m, 2H), 2.70 (d,
J
= 1.4 Hz, 2H),
1.89 (s, 6H), 1.54
-
1.50 (m, 1H), 1.31
(d,
J
= 9.9 Hz, 1H).
13
C NMR (500 MHz, CDCl
3
):
δ
(ppm)
177.7, 171.3, 137.8, 62.6, 55.4, 47.8, 45.2, 42.9, 37.3, 30.6.
HRMS (EI+): calcd. for
C
15
H
18
O
4
NBr [M+H]
+
:
m/z
= 355.0419; found
355.0435
.
IR (Thin Film, NaCl): 3456, 3065,
2981, 2881, 1774, 1739, 1703, 1464, 1450, 1426, 1392, 1371, 1360, 1328, 1283,
1215, 1192,
1159, 1110, 1037, 1014, 990, 942, 902, 883, 854, 828, 813, 804, 781, 771, 722 cm
-
1
.
Synthe
sis of Norbornene
-
Polylactide (L
-
MM
)
A flame
-
dried Schlenck tube was charged with
1
(
233
.9 mg,
1.13 mmol) and
racemic
3,6
-
dimethyl
-
1,4
-
dioxane
-
2,5
-
dione (6.096g,
42.3 mmol) along with
tin (II) 2
-
ethylhexanoate
(
2
mg,
5
μ
mol
)
. This mixture was put under three vacuum
-
argon cycles and then allowed to stir at
130
°
C for 2.5
hours. After cooling to room temperature the product was dissolved in
dichloromethane, filtered through a small pad of celite to remove catalyst and precipitated into
cold MeOH.
1
H NMR (500 MHz, CDCl
3
):
δ
(ppm)
6.28 (br t, 2H),
5.25
-
5.03 (m, 82
H), 4.40
-
4
.21 (m
, 3H), 3.82
-
3.68 (m, 2H) 3.26 (s, 2H), 2.70 (m,
2
H)
, 1.73
-
1.39 (m
,
247
H),
1.23 (br d,
J
=
8.5 Hz, 1H)
.
M
n
=
6.1 kg/mol.
GPC
-
MALLS:
M
n
= 6.3 kg/mol,
M
w
/M
n
=
1.20.
N
O
O
O
H
N
O
O
O
O
B
r
B
r
O
B
r
E
t
3
N
,
D
C
M
r
.
t
.
2
1
N
O
O
O
H
O
O
O
O
S
n
(
O
c
t
)
2
,
1
3
0
o
C
N
O
O
O
O
O
H
n
L
-
M
M
1
Synthesis of Norbornene
-
Polystyrene
(
S
-
MM
)
S
tyrene
(24 mL, 0.209 mol)
was
passed through basic aluminum oxide
and
added to an oven
-
dried Schlenk tube fitted with a septum. Then, the styrene underwent three freeze
-
pump
-
thaw
cycles and was subsequently frozen again.
CuBr (77.0 mg, 0.54 mmol) was next
added to the
frozen styrene un
der argon. This mixture was put under three vacuum
-
argon cycles before
allowing the
styrene to melt under argon. PMDETA (108
μ
L, 0.52 mmol) was then
added to the
mixture via a microsyringe and the solution stirred for 5 minutes. The
initiator,
2
(670.4 mg, 1.88
mmol),
was subsequently added to the Schlenck tube via syringe and th
e reaction mixture stirred
at 100
°
C. The reaction was
after 4 h
,
by cooling it quickly down to room temperature using dry
ice and adding THF to the mixture. The product
was passed through neutral aluminum oxide to
remove catalyst and precipitated into MeOH.
The product was purified by repeated precipitations
into MeOH until no remaining styrene was observed by NMR and further purified by silica gel
chromatography (dichlor
omethane).
1
H NMR (500 MHz, CDCl
3
):
δ
(ppm)
7.25
-
6.29 (br m, 260
H),
6.28 (br s
, 2H),
4.59
-
4.35 (m, 1H), 3.65
-
3.32 (m,
4
H), 3.22 (br s, 2H),
2.62 (br d,
J
= 6.6 Hz,
2 H),
2.56
-
1.55 (br m, 105 H),
0.99
-
0.83 (m, 6H)
.
M
n
=
5.8 kg/mol.
GPC
-
MALLS:
M
n
= 6.1
kg/
mol,
M
w
/M
n
=
1.02
.
General Procedure for Block Copolymerization of Two Macromonomers via ROMP
(A
-
L)
In a typical experiment, 150 mg of
each of the
macromon
omers
were added to separate
vials.
The desired amount of catalyst was added to the third vial. The vials were brought into a drybox
and the macromonomers were dissolved in the desired amount of THF ([M]
0
0.05
M) while the
catalyst was dissolved in 1.00 mL of THF. The desired amoun
t of catalyst solution was injected
via a m
icrosyringe to the solution of the
L
-
MM
since it
polymerize
s
faste
(
27
)
. When the first
macromonomer had polymerized
the solution of the second macromonomer
(
S
-
MM
)
was added
to the reaction mixture. This solution was allo
wed to stir for an additional
2
-
3
hours. The
reaction was moved out of
the dry box, quenched with butyl
vinyl ether and isolated by
precipitation into MeOH.
Conversion was 100% based on RI traces fr
om the GPC and i
solated
yields were generally over 85
%.
N
O
O
O
O
B
r
N
O
O
O
O
B
r
m
C
u
B
r
,
P
M
D
E
T
A
S
-
M
M
1
0
0
°
C
2
N
O
O
O
O
O
H
n
N
O
O
O
O
B
r
m
N
N
O
O
O
O
O
O
O
O
O
H
y
z
n
B
r
m
2
.
1
.
T
H
F
,
r
.
t
.
N
N
M
e
s
M
e
s
R
u
P
h
C
l
C
l
N
N
Synthesis of a Polylactide Brush Homopolymer
(M)
The
L
-
MM
(62.0 mg,
10.2
μ
mol) was weighed
in
to a vial. The catalyst
(2.6 mg, 3.58
μ
mol)
was
added to a separate vial. The vials were brought into the drybox and the
L
-
MM
was dissolved in
THF (
250
μ
L
) while the catalyst was dissolved in 1.00 mL of THF. The catalyst solution
(17
μ
L,
0.061
μ
mol)
was injected via a microsyringe to the solution o
f macromonomers and
the solution
allowed to stir for 2 hours. The reaction was moved out of
the dry box, quenched with butyl
vinyl ether and isolated by precipitation into MeOH.
GPC
-
MALLS
: M
n
= 1.04 x 10
6
g/mol,
M
w
/M
n
= 1.03.
Synthesis of a Polystyrene Brush Homopolymer
(N)
The
S
-
MM
(52.9 mg,
9.12
μ
mol) was weighed into a
vial. The catalyst (2.6 mg, 3.58
μ
mol) was
added to a separate vial. The vials were brought into the drybox and the
S
-
MM
was dissolved in
THF (200
μ
L) while the catalyst was dissolved in 1.00 mL of THF. The catalyst solution (14.5
μ
L, 0.052
μ
mol) was injected via a microsyringe to the solution of macromonomers and the
solution allowed to stir for 2 hours. The reaction was m
oved out of the dry box, quenched with
butyl vinyl ether and isolated by precipitation into MeOH. GPC
-
MALLS:
M
n
= 1.14
x 10
6
g/mol,
M
w
/
M
n
= 1.04.
An
nealing by Slow Evaporation
The solid polymer
(
40
-
50 mg)
was
put in a vial and
dissolved there in a
pprox.
10 mL of
solvent
(
dichloromethane or tetrah
ydrofuran). Then a glass
substrate
wa
s put
, vertically into the vial
and
the solvent allowed to evapor
ate
at room temperature.
The
glass
substrate
could be
subsequently
annealed
at 120°C in an oven for
2h
.
N
O
O
O
O
O
H
n
N
O
O
O
O
O
H
y
n
T
H
F
,
r
.
t
.
N
N
M
e
s
M
e
s
R
u
P
h
C
l
C
l
N
N
N
O
O
O
O
B
r
m
N
O
O
O
O
z
B
r
m
T
H
F
,
r
.
t
.
N
N
M
e
s
M
e
s
R
u
P
h
C
l
C
l
N
N
Thermal annealing between two glass
substrate
s
The solid polymer
(
10 mg)
was
sandwiched between two
glass
substrate
s
and
compressed with
a clamp.
. The glass
substrate
s, clamped together are then heated in an oven or a vacuum chamber
at 140° C
for 30 min.
SEM sample preparation
The samples were fractured on
glass
substrate
s and exposed to
fresh
RuO
4
vapor for
8
min
.
Supplementary table
Table S1
. Molecular weight information about the
(polynorbornene
-
g
-
polystyrene)
-
b
-
(polynorbornene
-
g
-
polylactide)
polymer series. a) The molar ratios used in the synthesis of these brush block copolymers
o
f the catalyst
(C) and the MMs.
b) Molecular weight and polydispersity index as measured by GPC
-
MALLS
. c) Approximation of
the size of each block as calculated usin
g NMR and GPC
results
(discussed elsewhere).
Sample
C:L
-
MM
:
S
-
MM
a
M
n,theo
(x 10
6
g/mol
)
M
n
(x 10
6
g/mol
)
b
PDI
(
M
w
/M
n
)
b
DP L
-
MM
c
DP S
-
MM
c
A
1:74:78
0.90
1.08
1.07
84
98
B
1:99:105
1.20
1.53
1.09
116
142
C
1:126:132
1.52
1.99
1.12
153
182
D
1:136:144
1.65
2.38
1.22
187
215
E
1:135:142
1.63
2.68
1.16
206
246
F
1:150:158
1.81
2.94
1.17
225
271
G
1:157:166
1.90
3.19
1.26
246
292
H
1:174:183
2.10
3.32
1.29
252
309
I
1:198:210
2.40
4.02
1.34
289
391
J
1:223:237
2.71
4.21
1.36
319
391
K
1:246:262
2.99
5.80
1.5
436
543
L
1:273:288
3.30
6.64
1.58
497
624