Download Bioinspired Infrared Detection Using Thermoresponsive

Bioinspired Infrared Detection Using
Thermoresponsive Hydrogel Nanoparticles
Supplementary Information
Zhen Luo,a Jun Chen,a Qingchen Shen, Jiaqing He, Hao Shan,
Chengyi Song, Peng Tao, Tao Deng,* Wen Shang*
State Key Laboratory of Metal Matrix Composites
Shanghai Jiao Tong University
Shanghai 200240, People’s Republic of China
School of Materials Science and Engineering
Shanghai Jiao Tong University
Shanghai 200240, People’s Republic of China
aZhen
Luo and Jun Chen contributed equally to this work.
authors: Professor Wen Shang, [email protected] or
Professor Tao Deng, [email protected].
*Corresponding
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Table S1. The chemicals used in the synthesis of poly(NIPAM-co-AAc) hydrogel NPs.
Diameter(nm)
NIPAM(g)
AMPS (g)
BIS(g)
SDS(g)
AAc(g)
K2S2O8(g)
Sample 1
120
3.470
0.030
0.105
0.020
0.070
0.015
Sample 2
170
3.470
0.030
0.050
0.005
0.070
0.014
Sample 3
300
3.470
0.030
0.050
0.000
0.140
0.070
*The full names of the chemicals in the table are as the following:
NIPAM: N-Isopropyl acrylamide
AMPS:2-acrylamido-2-methyl-1-propanesulfonic acid
AAc:Acrylic acid
BIS:N,N’-methylene-bis-acrylamide
SDS:Sodium dodecyl sulfate
K2S2O8:Potassium persulfate
FTIR and NMR characterization of PNIPAM NPs.
Figure S1 shows the FT-IR spectra for the PNIPAM NPs with three different particle
sizes. The wide absorption band at 3100-3500 cm-1 region includes both the –NH stretching
(low end) and the –OH stretching (high end); the methyl and methane absorption peaks are at
2936 cm-1-2876 cm-1; the peak at 1715 cm-1 is the stretching peak of carboxylic acids (C=O);
the acylamino C=O stretching vibration peak is at about 1645 cm-1; peak at 1557 cm-1 can be
assigned to N-H bending peak; peak at 1457 cm-1 is the methyl group C-H bend vibration
peak; peaks at 1368 cm-1 and 1387 cm-1 correspond to isopropyl umbrella deformation; peak
at 1235 cm-1 is the carboxylic acids C-O stretch peak. The differences in the FTIR spectra for
particles of difference sizes might be due to the differences in the internal molecular packing
and also the minute absorption of water vapor from the air.
The FTIR spectra confirms that the PNIPAM hydrogel is constituted by hydrophilic
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group of acylamino (-CONH-) and hydrophobic group of isopropyl (-CH (CH3)2). The spectra
also confirm the existence of carboxylate (-COOH) group.
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Figure S1. FTIR spectra for poly(NIPAM-co-AAc) hydrogel NPs with different sizes. (a)
120-nm NPs; (b) 170-nm NPs; (c) 300-nm NPs.
The 1H NMR spectra of the hydrogel NPs were recorded on a Bruker BioSpin GmbH 600
MHz NMR spectrometer using D2O as the solvent. As shown in Figure S2, the NMR spectra for
all the NP samples are similar, which is also consistent with the reported spectra for
poly(NIPAM-co-AAc). The spectra confirm the existence of the hydrophobic groups and
hydrophilic groups of the pNIPAM hydrogel that are critical to the IR detection function of the
NPs.
Figure S2. NMR spectra for hydrogel NPs with different sizes.(a)molecular structure of the
hydrogel NPs; (b) NMR spectrum for hydrogel NPs with size of 120 nm; (c) NMR spectrum
for hydrogel NPs with size of 170 nm ; (c) NMR spectrum for hydrogel NPs with size of 300
nm.
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Calculation of hydrogel NP size:
The sizes of the hydrogel NPs were calculated based on the assumption that the volumes
of the hemisphere particles on the Si wafer surface (V1) are the same as the spherical particles
in hydrophobic state in solution (V2).
Using the following equations:
(1)
(2)
(3)
Here h is the hight of the hemisphere and d is the diameters of the hemisphere from the
analysis of the AFM images. The diameters (D) of the three NP samples were thus calculated
to be 120 nm, 170 nm and 300 nm.
Figure S3 are the changes of transmittance for 0.5 oC temperature increase at the
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temperature range of 30 - 34 C for hydrogel NPs with sizes of 120 nm, 170 nm, and 300 nm.
Figure S3. Change of transmittance for 0.5 °C temperature increase at the temperature range
of 30 - 34 °C for hydrogel NPs with different sizes. a) 120 nm; b) 170 nm; c) 300 nm.
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Figure S4 are the changes of transmittance for 0.5 °C temperature increase at the
temperature range of 30 - 34 °C for 120 nm hydrogel NPs with solid contents of 0.09%,
0.30%, 0.45%, 0.60%, and 0.90%.
Figure S4. Change of transmittance for 0.5 oC temperature increase at the temperature range
of 30 – 34 oC for 120-nm hydrogel NPs with different solid contents. a) 0.09%; b) 0.30%; c)
0.45%; d) 0.60%; e) 0.90%.
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