Hydrogels and Cryogels

Nuclear Magnetic Resonance Studies of Interfacial Phenomena 

FIGURE 5.35 CLSM images of HEMA-AGE hydrogel (sample A) in (a) hydrated and (b) dried states with the pore (c) size and (d) wall thickness distribntions. (Adapted from Savina, I.N., Gun ko, V.M., Turov, YN. et al., Noninvasive structural characterisation of macroporous cross-linked polymer and protein hydrogels. Soft Matter, 7, 4276-4283, 2011, Copyright 2011, with permission from The Royal Society of Chemistry.) 

The pore sizes of samples A, B, and C were mainly in the range of 3-100 xm with mean pore sizes of 64, 47, and 41.4 im, respectively (Table 5.5). Gel D displayed a narrower pore size distribution (3-83 am) with a mean pore size of 25.7 im. The wall thickness distribution of gel B calculated using Image granulation plug-in was narrower (2-14 pm) while the gels A, C, 

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Fig. 19 Thermally induced collapse of poly(A, Af-diethylacrylamide) hydrogel (curve 1) and cryogel samples (curve 2) upon increasing the temperature from room temperatiffe to 60 °C. The variation in the volume of the gel samples is shown as a function of the deswelling time. Synthesis conditions initial monomer concentration 5.66 wt% molar ratio of vinyl to divinyl monomers 200 1 gelation temperature +20 °C (curve 1) and — 10 C (curve 2). (From [172] with permission from Springer)...

Fig. 9 Photographs of (a) fibroin hydrogels and (b) cryogels formed at =50 and —18 °C, respectively, during the compression tests. Csf = 4.2 % EGDE = 20 mmol/g TEMED = 0.10 %. Arrows indicate the direction of piston movement, (c) Stress-strain curves of these gel samples are shown as the dependence of the nominal stress a on the degree of compression. (Erom [50] with permission from the American Chemical Society)...

Abstract Poly(vinyl alcohol) (PVA) is a hydrophilic and biocompatible polymer that can be crosslinked to form a hydrogel. When physically crosslinked using a freeze-thaw cycling process, the product hydrogel or cryogel (PVA-C) possesses... 

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