supporting information for: ionic liquid mediated auto-templating
TRANSCRIPT
Supporting Information for:
Ionic Liquid Mediated Auto-Templating Assembly of CaCO3-Chitosan Hybrid Nanoboxes and Nanoframes
Anna Chen, Zhiping Luo, and Mustafa Akbulut*,a
aDepartment of Chemical Engineering, Materials Science and Engineering Program, Texas
A&M University, 230 Jack E. Brown Engineering Building, College Station, TX 77843 USA.
E-mail: [email protected]; Tel: (979) 847-8766
Experimental Procedures: For the synthesis of CaCO3-chitosan nanostructures, calcium
chloride dehydrate (99+%), 1-butyl-3-methylimidazolium chloride (≥ 98%), medium molecular
weight chitosan, and sodium carbonate (≥ 99%) were purchased from Sigma Aldrich. All
chemicals were used as received. 4.01 g [BMIM][Cl], 0.029 g CaCl2, and 0.02 g chitosan were
put inside a vial and melted at 100°C. The mixture was sonicated with a sonication probe
(Misonix XL-2000) for 2 min to dissolve the CaCl2 and chitosan solid. After the solids dissolved
in solution, 0.2 mL of 1M Na2CO3 solution was dispensed into the vial. The solution was
sonicated for 1 min with the sonication probe at a temperature of 100°C. Lastly, the sample was
dialyzed using dialysis membrane (Spectrum Laboratories MWCO: 12,000 - 14,000 daltons).
Analysis Methods: Nanostructures were viewed with transmission electron microscope (FEI
Tecnai G2 F20 FE-TEM), and scanning electron microscope (JEOL JSM-7500F). Samples for
scanning electron microscopy were coated with 4 nm of Pt/Pd. Analysis of nanostructure crystal
structure was performed using x-ray diffraction (Bruker-AXS D8 Advanced Bragg-Brentano).
After dialysis the samples were filtered, dried overnight, and powderized with mortar and pestle.
The samples were scanned from 20 to 70° (2θ). Cu anode was used with λ = 1.54 angstroms. The
voltage was set at 40 kV, and the current was set to 40 mA. Samples were scanned at a rate of
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1°/min with a step size of 0.015°. The diffraction pattern from a nanoframe were obtained with
transmission electron microscope (JEOL JEM-2010). Thermal gravimetric analysis was
performed using TGA Q50 instrument. After dialysis was completed, the samples were filtered,
dried overnight, and powderized. Samples were scanned from 25 to 1000˚C at a rate of
15˚C/min.
Fourier Transform Infrared Spectroscopy (FTIR): In order to determine whether chitosan
chemically bonded with CaCO3, FTIR spectroscopy was performed (Bruker Alpha-P). CaCO3
prepared in water yielded peaks at similar wavelengths to those of CaCO3 prepared in
[BMIM][Cl] (Fig. S1 and S2). The three peaks located from 700-1400 cm-1 can be attributed to
the C-O bonding of CaCO3. The weak peak at about 1790 cm-1 is due to the C=O bonding of
CaCO3. FTIR was also performed on the CaCO3-chitosan hybrid (Fig. S3). The peaks from 600-
1400 cm-1 can be attributed to the C-O, C-C, and C-N bonding of chitosan and CaCO3. Peaks
from 1640-1800 cm-1 arise from the C=O bonding of CaCO3. Lastly, peaks from 2500-3320 cm-1
are due to the C-H, N-H, and O-H bonds in chitosan. A significant peak shift is observed for the
1388.45 cm-1 peak in the Fig. S1 and 1393.69 cm-1 peak in Fig. S2 to the 1404.56 cm-1 peak in
Fig. S3. This may be caused by the absorption of chitosan to CaCO3 surface.
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0.05
0.10
0.15
0.20
0.25
0.30
179
4.6
2
1388
.46
871
.40
Abs
orba
nce
Wavenumber (cm-1)
710.
38
Fig. S1 FTIR spectra of CaCO3 prepared in water.
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500 1000 1500 2000 2500 3000 3500 40000.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
17
95
.00
13
93
.69
87
3.8
97
12
.67
Ab
sorb
an
ce
Wavenumber (cm-1)
Fig. S2 FTIR spectra of CaCO3 prepared in ionic liquid [BMIM][Cl].
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0.02
0.04
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0.1
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94
.65 33
20.1
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28
73
.42
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.47
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.22
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.58
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64
.66
10
27
.44
14
04
.50
70
8.9
6Abs
orb
ance
Wavenumber (cm-1)
87
1.1
2
Fig. S3 FTIR spectra of CaCO3-chitosan hybrid prepared in ionic liquid [BMIM][Cl].
SEM of pure CaCO3: SEM images were taken of pure CaCO3 made in water and in [BMIM]Cl
medium (Fig. S4). These samples were prepared in the same manner as the CaCO3-chitosan
hybrid nanostructures. The CaCO3 formed was spread upon carbon tape and coated with 4 nm of
Pt/Pd. It was found that the dimensions of the pure CaCO3 in water and [BMIM][Cl] are 4.79 ±
1.70 x 3.94 ± 1.52 μm and 340 ± 144 x 273 ± 116 nm respectively.
Supplementary Material (ESI) for Chemical CommunicationsThis journal is (c) The Royal Society of Chemistry 2011
Fig
SEM im
nanostruc
wafer an
complete
F
Therm
mg of 24
S6,7 that
loss from
in both sa
sample th
g. S4 SEM im
mage of soli
cture was tak
d coated wit
ely removed
Fig. S5 SEM
mal Gravime
4 h sample an
t chitosan de
m 50 to 150˚C
amples. In th
here was 59
a
mage of CaC
id CaCO3 b
ken before d
th 4 nm of P
by the spin
M image of s
etric Analys
nd 16.06 mg
composed a
C was attribu
he 24 h samp
wt% CaCO3
CO3 prepared
before dial
dialysis was
Pd/Pt. The im
coater and re
olid CaCO3-
sis: CaCO3-c
g of 90 h sam
around 300˚C
uted to wate
ple there wa
3 and 34 wt%
d in (a) wate
ysis: SEM
performed.
mage is not v
esidual [BM
-chitosan hy
chitosan sam
mple were us
C while calci
r loss in the
s 55 wt% Ca
% chitosan.
b
er and (b) ion
image of s
The sample
very sharp b
MIM][Cl] cau
ybrid nanostr
mples were d
sed in the ana
ite decompo
samples. Th
aCO3 and 38
nic liquid [B
solid CaCO3
e was spin co
because [BM
used the sam
ructure befor
dialyzed for 2
alysis. It can
osed at about
here was abo
8 wt% chitos
BMIM][Cl].
3-chitosan h
oated on a si
MIM][Cl] wa
mple to charg
re dialysis.
24 and 90 h.
n be seen in F
t 750˚C. Wei
out 7 wt% w
san. For the
hybrid
ilicon
as not
ge.
8.15
Fig.
ight
ater
90 h
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Fig. S6. Thermal gravimetric analysis result of CaCO3-chitosan sample after 24 h dialysis.
Fig. S7. Thermal gravimetric analysis result of CaCO3-chitosan sample after 90 h dialysis.
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iv. W
eigh
t (%
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Supplementary Material (ESI) for Chemical CommunicationsThis journal is (c) The Royal Society of Chemistry 2011