Equilibrium swelling

VP = vapor pressure of solvent glc = ga.sliquidchromatography, SE = swelling equilibria Op = osmotic pressure. 

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. 

Siegel, R, A, Hydrophobic Weak Polyelectrolyte Gels Studies of Swelling, Equilibria and Kinetics. Vol. L 09, pp. 233-268. 

RA Siegel. Hydrophobic weak polyelectrolyte gels—Studies of swelling equilibria and kinetics. Adv Polym Sci 109 233-267, 1993. 

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

RA Siegel. pH sensitive gels—Swelling equilibria, kinetics and applications for drug delivery. In J Kost, ed. Pulsed and Self-Regulated Drug Delivery. Boca Raton, FL CRC Press, 1990, pp 129-157. 

Siegel, R. A., pH-Sensitive Gels Swelling Equilibria, Kinetics, and Applications for Drug Delivery, in Pulsed and Self-Regulated Drug Delivery (J. Kost Ed.), pp. 129-155. CRC Press, Boca Raton (1990). 

Figure 10 presents the swelling equilibria of the NIPA gel in the presence of the polar organic additives of normal alcohols, urea and glycerol. Figure 11 shows... 

Swelling equilibria obtained with the thermoshrinking /V-alkylacrylamide gels in water indicated that their phase transition behavior is strongly dependent on the hydrophobicity of the gels. In addition, the swelling behavior was shown to... 

Hydrophobic Weak Polyelectrolyte Gels Studies of Swelling Equilibria and Kinetics... 

In many of the experiments to be described, buffers were used to stabilize the pH of the system, obviating the need for large bath volumes or pH-stat. It was assumed initially that buffering would have only secondary effects on our measurements. As will be seen, however, the nature of the buffer can have profound effects on both swelling equilibria and kinetics. This result is important for any ionizable gel system that one expects to use for therapeutic purposes, since such systems will either be stored in pH-buffers, or encounter physiologic buffering when placed in contact with body fluids. 

We have attempted without success to show that swelling equilibria in the glassy state can be reached from more than one direction. Specifically, we have swollen the gels to equilibrium at low pH s and then reintroduced them into solutions at pH values above the critical pH. The gels fail to deswell to the same EWF as is observed when swelling is from the dry state. Examples of such deswelling curves will be found in the Sect. 6, in which these experiments will be discussed in more detail. 

Fig. 4a, b. Swelling equilibria for MMA/DMA 70/30 gels in unbuffered uni-univalent salt solutions with various anions and cations. pH 4.0, I = 0.1 M. T = 25°C a Sodium salt solutions with different anions, b Chloride salt solutions with different cations. [Adapted from Ref. 18 with permission.]... 

The second novelty of our work is the elucidation of the role of pH-buffers in swelling equilibria and kinetics. It is interesting to note that most physical chemists choose not to use buffers because they complicate the system under study. On the other hand, any ultimate biological application of gels is likely to involve some sort of buffered medium. As we have shown, buffer properties such... 

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