Supporting Information for: Ionic Liquid Mediated Auto-Templating

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

Supplementary Material (ESI) for Chemical CommunicationsThis journal is (c) The Royal Society of Chemistry 2011

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.

500 1000 1500 2000 2500 3000 3500 40000.00

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.


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].

500 1000 1500 2000 2500 3000 3500 40000.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

61

0.1

4

17

94

.65 33

20.1

7

28

73

.42

25

15

.47

16

47

.22

11

51

.58

10

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.


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


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.

0

2

4

6

8

10

12

Der

iv. W

eigh

t (%

/min

)

20

40

60

80

100

Wei

ght (

%)

200 400 600 8000 1000

Temperature (°C)

0

2

4

6

8

2

10

Der

iv. W

eigh

t (%

/min

)

40

60

80

100

20

120

Wei

ght (

%)

200 400 600 8000 1000

Temperature (°C)


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Supporting Information for: Ionic Liquid Mediated Auto-Templating