Hydrogels ionized

Fig. 5. Influence of pressure on swelling of two samples of partly ionized PAAm hydrogels in 0.01 N aqueous NaCl solution solid curve — uniaxial, dashed curves — isotropic swelling as obtained by calculation. Points on the y-axis correspond to the free swelling. From Dubrovskii etal. [22]...

Holz, M Lucas, O Muller, C, NMR in the Presence of an Electric Current, Simultaneous Measurements of Ionic Mobilities, Transference Numbers, and Self-Diffusion Coefficients Using an NMR Pulsed-Gradient Experiment, Journal of Magnetic Resonance 58, 294, 1984. Hooper, HH Baker, JP Blanch, HW Prausnitz, JM, Swelling Equilibria for Positively Ionized Polyacrylamide Hydrogels, Macromolecules 23, 1096, 1990. 

The use of ionizing radiation to induce cross-linking is another important technique for producing hydrogels from linear water-soluble polymers. When such polymers are bombarded by ionizing radiation, either in the bulk state or in solu-... 

HH Hooper, JP Baker, HW Blanch, JM Prausnitz. Swelling equilibria for positively ionized polyacrylamide hydrogels. Macromolecules 23 1096-1104, 1990. 

Fig. 5. Expansion (swelling) of a cationic hydrogel due to ionization of pendent groups, at specific pH values.

Degree of ionization an increase in the ionic content of a hydrogel increases the hydrophilicity and results in a higher degree of swelling. 

These expressions are for an anionic hydrogel and could easily be derived for a cationic gel. Here the term ic2/z represents the concentration of anions along the polymer chains with i being the ionization. Substitution into Eq. (24) yields... 

Mechanism of Release Release from Hydrogels Possessing Ionizable... 

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