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Electronic Supplementary Information for the
Journal of Materials Chemistry
Corrugated and nanoporous silica microspheres: synthesis
by controlled etching, and improving their chemical
adsorption and application in biosensing
Tewodros Asefa* and Yan-Li Shi
Department of Chemistry, Syracuse University, 111 College Place,
Syracuse, NY 13244, USA
E-mail: [email protected];
Fax: +1-315-443-4070; Tel: +1-315-443-3360
Table S1. Pore-volume and surface area data of as-prepared and etched silica
microspheres.
Silica Nanosphere Samples Surface Area (m2/g) Pore Volume (cm3/g)
Si450 4.8 0.015
Si450-KCN-H4 5.3 0.019
Si450-KCN-H8 6.3 0.030
Si450-KOH-H4 5.5 0.040
Si450-KOH-H8 8.3 0.035
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(A) (B) (C)
Figure S1. Enlarged TEM image of silica microspheres of average diameter of (A)
~450, (B) ~250 and (C) ~110 nm and that are labeled as Si450, Si250 and Si110,
respectively. The full images with scale bars are shown on Fig. 1 in the paper.
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(A) (B) (C)
(I)
(II)(A) (B) (C)
Figure S2. Enlarged TEM images of 100 μL, 10 mg/mL of silica microspheres of
average diameter of 450 nm (Si450) after etching with (I) 1 mL of high KCN
concentration (0.03 M, pH = 11.00) for (A) 1, (B) 4, and (C) 8 h resulting in samples
Si450-KCN-H1, Si450-KCN-H4, and Si450-KCN-H8, respectively; and (II) 1 mL of
high KOH concentration (0.03 M, pH = 12.60 for (A) 1, (B) 4, and (C) 8 h resulting
in samples Si450-KOH-H1, Si450-KOH-H4, and Si450-KOH-H8, respectively.
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FF
200 nm 100 nm
(B)(A)
Figure S3. TEM images of 100 μL, 10 mg/mL of silica microspheres of average
diameter of 450 nm (Si450) after etching for 4 h with 1 mL of low KOH concentration
(pH = 10.61), which is of the same pH as the high concentration KCN used.
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(A) (B)
(C)
Figure S4. Enlarged TEM images of 100 μL, 10 mg/mL of silica microspheres of
average diameter of 250 nm (Si250) after etching with 1 mL of higher KCN
concentration (0.03 M, pH = 11.00) for (A) 1, (B) 4, and (C) 8 h resulting in samples
Si250-KCN-H1, Si250-KCN-H4, and Si250-KCN-H8, respectively.
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200 nm 100 nm 50 nm
(C)(A)(B)
Figure S5. TEM images of 100 μL, 10 mg/mL of silica microspheres of average
diameter of 110 nm (Si110) after etching with 1 mL of higher KCN concentration (0.03
M, pH = 11.00) for (A) 4, (B) 13 and (C) 23 h under static condition.
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428.
60
778.
44
1066
.55
1628
.36
3158
.98
1066
.27
2341
.71
2360
.4429
01.2
0
2987
.25
3422
.66
50
52
54
56
58
60
62
64
66
68
70
500 1000 1500 2000 2500 3000 3500 Wavenumbers (cm-1)
Si 450-KCN-H8Si 450-KCN-H4
Si 450Si 450-KOH-H4
air
% T
Wavenumber (cm-1)
Figure S6. FT-IR spectra of silica microspheres of average diameter of 450 nm (Si450)
before and after etching with KCN and KOH solution.