DESIGN OF SUPERMACROPOROUS BIOMATERIALS VIA GELATION AT SUBZERO TEMPERATURES —CRYOGELATION - Advanced Biomaterials: Fundamentals, Processing, and Applications - page 503

60

19 °C 37 °C 19 °C 37 °C

pNIPA6% (1/10)

19 °C

50

pNIPA10% (1/10)

40

pNIPA6% (1/100)
pNIPA10% (1/100)

30

20

10

0

0 2 4 6 8 10

Time (h)

Figure 14.9. Swelling ratios of the pNIPAAm gels in distilled water at room temperature.
Reproduced from [Galaev et al., 2007] with permission.

70

55

40

25

10

Gel 22°C-5% Gel 0.5°C-5% Gel 0.5°C-10% Gel (-20)°C-10%

Figure 14.10. The time dependence of swelling of pNIPAAm-MGs produced under semi-
frozen conditions from polymerization feeds with total monomer concentrations 6 and 10%
and MBAAm(cross-linker)/NIPAAm ratios 1/10 and 1/100 mol/mol. Reproduced from [Zhang
and Chu, 2003] with permission.

of pNIPAAm-MGs to a temperature change from 19 °C to 37 °C was very fast.
The lower the total monomer concentration and the cross-linking degree of
pNIPAAm-MGs, the higher was the change in swelling and the larger amplitude
of mechanical deformation occurred when the temperature was changed from
19 ° C to 37 ° C and backwards (Figure 14.10 ).