Assembly of metal nanoparticles on regenerated
fibers from wood sawdust and de-inked pulp: Flexible
substrates for surface enhanced Raman scattering
(SERS) applications
Xian-Ming Kong · Mehedi Reza · Yi-Bo Ma · Juan-P. Hinestroza · Esko
Ahvenniemi · Tapani Vuorinen
X.-M. Kong() · Y.-B. Ma · T. Vuorinen
Department of Forest Products Technology, School of Chemical
Technology, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland.
e-mail: kong.xianming@aalto.fi.
M. Reza
Department of Applied Physics, Aalto University, P.O. Box 11100,
FI-00076 Aalto, Finland
J.-P. Hinestroza
Department of Fiber Science and Apparel Design, Cornell University,
Ithaca, NY 14853, USA
Esko Ahvenniemi
Department of Chemistry, School of Chemical Technology, Aalto
University, P.O. Box 16100, FI-00076 Aalto, Finland
1
Fig. S1 TEM images of Ag NPs.
2
0.8
0.7
0.6
Absorbance
0.5
0.4
Fiber-Ag NPs
0.3
0.2
Fiber
0.1
0.0
300
350
400
450
500
550
Wavelength(nm)
Fig. S2 Absorption spectra of fiber and fiber-Ag
Estimation the amount of AgNPs incorporated in the fiber
The concentration of Ag colloids used for UV-vis measurement is a quarter of
original concentration, the absorbance of the diluted Ag colloid (before
incorporated in fiber) at 405 nm was A = 1.65 with the optical path length of the
cuvette l = 1 cm. The molar extinction coefficient of AgNP colloidal solution is ε
= 3 × 1011 M−1 cm−1.S1 According to the Lambert-Beer’s law A = εlc, the
concentration of the diluted Ag colloidal solution was c = A/εl =0.55 × 10−11 M,
after thus, the concentration of the original Ag colloidal solution was cAg = 4c
=2.2 × 10−11 M. The total amount of AgNPs in 10 mL of colloidal solution was
MAg = 2.2 ×10−11 ×10 × 10−3 = 2.2 ×10−13 molar. After incorporated in 7 mg of
cationized DIP fiber, the absorbance of the diluted Ag colloid(aftert incorporated
3
in fiber) at 405 nm was A = 1.29. The amount of AgNPs incorporated in fiber
MAg-f =(1.65 - 1.29)/1.65 ×MAg = 0.48×10−13 molar.
Ag colloids
0
-5
a
b
b'
c
c'
Zeta potential(mv)
-10
-10,5
-15
-15,2
-20
-25
-24,7
-30
-35
-34,2
-40
-45
-45,1
-50
Fig. S3 Zeta potential of Ag colloids before (a) and after exposure to 7 mg (b, b’) and
14 mg (c, c’) cationized fibers (deinked pulp). The fibers were cationized with (b, c)
or without ( b’, c’) presoaking in water prior to the derivatization..
4
Fig. S4 Microscope image of cationized regenerated fiber (saw dust) dried (a), wetted
(b) and redried (c) fiber.
5
intensity(a.u.)
Fig. S5 SEM image of Ag-fiber after dried from wet condition
500
1000
1500
2000
-1
raman shift(cm )
Fig. S6 Raman spectra of R6G solutions (10-6 M) with fiber(DIP)
6
Intensity(a.u.)
Fiber(sawdust)-Ag
Intensity(a.u.)
500
1000
1500
2000
2500
3000
3500
-1
Raman shift(cm )
(a)
(b)
(c)
500
1000
1500
2000
-1
Raman shift(cm )
Fig. S7 Raman spectra of R6G solutions (10-6 M) with (a) and without (b) AgNPs
coated regenerated fiber (saw dust) and AgNPs coated regenerated fiber (saw dust)
without R6G (c) (the inner figure is curve (c) in lower scale).
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Fig. S8 (a) AFM image of AgNPs-assembled glass slide pre-immobilized with
APTMS and (b) absorption spectra of the slide before and after assembling AgNPs.
8