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Study of synthesis parameters on the physical properties and morphology of smart PNIPAAm hydrogels

Luíza Braga Ferreira dos Santos
Luíza Braga Ferreira dos Santos
, 
Francielly Moura de Souza Soares
Francielly Moura de Souza Soares
, 
Emília Santos Monteiro
Emília Santos Monteiro
, 
Maria Elisa Rodrigues Coimbra
Maria Elisa Rodrigues Coimbra
 et 
Carlos Nelson Elias
Carlos Nelson Elias
   | 13 sept. 2022
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Publié en ligne: 13 sept. 2022
Pages: 196 - 205
Reçu: 14 mars 2022
Accepté: 31 mai 2022
DOI: https://doi.org/10.2478/msp-2022-0020
Mots clés
© 2022 Luíza Braga Ferreira dos Santos et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1

Sample H1.0 after gelation
Sample H1.0 after gelation

Fig. 2

Swelling ratios of the hydrogels at room temperature and 37°C in (a) stirred samples and (b) unstirred samples
Swelling ratios of the hydrogels at room temperature and 37°C in (a) stirred samples and (b) unstirred samples

Fig. 3

1H NMR spectra of Nipam, H1.0, H2.0, H3.0, and H4.0 (500 MHz, D2O).
1H NMR spectra of Nipam, H1.0, H2.0, H3.0, and H4.0 (500 MHz, D2O).

Fig. 4

FTIR-ATR spectra of all hydrogel samples
FTIR-ATR spectra of all hydrogel samples

Fig. 5

(a) EDS spectrum of hydrogel H1.A and (b) image of the region analyzed by EDS
(a) EDS spectrum of hydrogel H1.A and (b) image of the region analyzed by EDS

Fig. 6

XRD patterns of the hydrogels.
XRD patterns of the hydrogels.

Fig. 7

SEM morphologies of the samples of H2.0, H3.0, and H4.0. Magnification of the sample of H2.0: (a) 600 ×; (b) 2,500 ×; (c) 8,000 ×. Magnification of the sample of H3.0: (d) 600 ×; (e) 2,500 ×; (f) 5,000 ×. Magnification of the sample of H4.0: (g) 600 ×; (h) 2,400 ×; (i) 10,000 ×
SEM morphologies of the samples of H2.0, H3.0, and H4.0. Magnification of the sample of H2.0: (a) 600 ×; (b) 2,500 ×; (c) 8,000 ×. Magnification of the sample of H3.0: (d) 600 ×; (e) 2,500 ×; (f) 5,000 ×. Magnification of the sample of H4.0: (g) 600 ×; (h) 2,400 ×; (i) 10,000 ×

Fig. 8

Morphologies of the sample of H1.0. Magnifications: (a) 600 ×; (b) 2,500 ×; (c) 10,000 ×.
Morphologies of the sample of H1.0. Magnifications: (a) 600 ×; (b) 2,500 ×; (c) 10,000 ×.

Fig. 9

Morphologies of the samples of H1.A, H2.A, and H3.A. Magnification of the sample of H1.A: (a) 600 ×; (b) 2,500 ×; (c) 5,000 ×. Magnification of the sample of H2.A: (d) 600 ×; (e) 2,500 ×; (f) 10,000 ×. Magnification of the sample of H3.A: (g) 600 ×; (h) 2,500 ×; (i) 8,000 ×
Morphologies of the samples of H1.A, H2.A, and H3.A. Magnification of the sample of H1.A: (a) 600 ×; (b) 2,500 ×; (c) 5,000 ×. Magnification of the sample of H2.A: (d) 600 ×; (e) 2,500 ×; (f) 10,000 ×. Magnification of the sample of H3.A: (g) 600 ×; (h) 2,500 ×; (i) 8,000 ×

Fig. 10

PNIPAAm hydrogels’ thermogravimetric analysis (TGA)
PNIPAAm hydrogels’ thermogravimetric analysis (TGA)

NMR 1H Spectra results

Groups Chemical dislocation (ppm) Integration ratio/number of hydrogens involved
H1.0 1.22 6.04 / 6
1.66 1.89 / 2
2.09 1.17 / 1
3.98 1.00 / 1
H2.0 1.08 6.00 / 6
1.64 2.19 / 2
1.96 1.17 / 1
3.83 1.16 / 1
H3.0 1.22 5.93 / 6
1.78 1.98 / 2
2.10 1.33 / 1
3.97 1.00 / 1
H4.0 1.21 6.00 / 6
1.68 2.32 / 2
2.11 1.12 / 1
3.98 0.85 / 1

Semiquantitative chemical composition (wt%) of the samples using EDS analysis

Groups Carbon Oxygen Nitrogen Platinum
H1.A 77.70 8.09 12.24 1.97
H1.0 72.51 4.86 3.93 18.70
H2.A 74.76 4.00 0.05 21.20
H2.0 80.19 10.90 5.42 3.48
H3.A 75.76 6.02 0 18.21
H3.0 73.65 7.03 0 19.32
H4.0 65.41 7.81 0 26.78

Hydrogel groups, reagents concentration, and synthesis process

Groups NIPAM (mmol) MBA (mmol) APS (mmol) NMB (mmol) Mol % Magnetic stirring
H1.A* 2.21 0.135 0.078 0.097 87.7×5.4×3.1×3.8 Yes
H2.A* 2.26 0.239 0.074 0.101 84.5×8.9×2.8×3.8 Yes
H3.A* 2.22 0.446 0.059 0.076 79.3×15.9×2.1×2.7 Yes
H1.0 2.21 0.132 0.076 0.097 87.8×5.2×3.2×3.8 No
H2.0 2.22 0.235 0.075 0.102 84.4×8.9×2.8×3.9 No
H3.0 2.23 0.443 0.057 0.074 79.5×15.8×2.3×2.6 No
H4.0 2.22 0.443 0.076 0.075 78.9×15.7×2.8×2.6 No

Thermogravimetric data of the hydrogels

Sample 1st event 2nd event 3rd event
Tpeak (°C) Residue Tmax (°C) Tpeak (°C) Residue Tmax (°C) Tpeak (°C) Residue
H1.A 74 4% 265 291 20% 349 381 61%
H1.0 54 5% 262 286 18% 360 397 71%
H2.A 104 7% 342 389 67% - - -
H2.0 56 6% 271 307 20% 378 412 69%
H3.A 111 6% 346 381 62% - - -
H3.0 61 4% 259 279 21% 350 383 66%
H4.0 65 4% 260 281 23% 351 376 65%
eISSN:
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Langue:
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Sujets de la revue:
Materials Sciences, other, Nanomaterials, Functional and Smart Materials, Materials Characterization and Properties
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