Hydrogels Subject

Fig. 16 Swelling measurements of PVA-y-CD hydrogels subjected to five freezing-thawing cycles as a function of time for different PVA y-CD molar ratios (filled box) PVA 10% (gml ) (filled, circle) PVA/y-CD (26 1) (filled triangle) PVA/y-CD (39.5 1) and (filled inverted triangle) PVA/y-CD (53.4 1)...

Fig. 6 Release profiles of BSA from PVA hydrogels subjected to 1 filled circle), 2 (open circle), 3 (filled triangle), and 6 (open triangle) FTCs. These hydrogels were composed of 10 % (w/w) PVA, 0.10 % (w/w) BSA. The freezing and thawing rates were both at 0.50 °C/min...

Li, H., Ng, T. Y., Yew, Y. K. and Lam, K. Y. (2007) Meshless Modeling of pH-Sensitive Hydrogels Subjected to Coupled pH and Electric Field Stimuli Young Modulus Effects and Case Studies, Macromol. Chem. Phys. 208, 1137-46. 

FIGURE 13.15 Drug release over 10-min intervals from a hydrogel subjected to oscillatory... 

Determination of cross-link density from compression experiments is perhaps the most effective means of determining cross-link density as long as samples of the appropriate geometry can be prepared. When a hydrogel is subjected to an external force, it undergoes elastic deformation which can be related to the effective cross-link density of the network [63,99], Here the measurements made to extract cross-link density from polymer deformation are briefly discussed. 

The complexity of the swelling kinetics of hydrogels means that only the simplest cases can be modeled quantitatively. Thus this section focuses on identification of rate-influencing phenomena and data analysis rather than the extensive theoretical modeling of the kinetic phenomena that has been done on this subject. Reviews of theoretical modeling include those by Peppas and Korsmeyer [119], Frisch [120], and Windle [121],... 

The structure of hydrogels that do not contain ionic moieties can be analyzed by the Flory Rehner theory (Flory and Rehner 1943a). This combination of thermodynamic and elasticity theories states that a cross-linked polymer gel which is immersed in a fluid and allowed to reach equilibrium with its surroundings is subject only to two opposing forces, the thermodynamic force of mixing and the retractive force of the polymer chains. At equilibrium, these two forces are equal. Equation (1) describes the physical situation in terms of the Gibbs free energy. 

Silica applied as a support for catalysts is an X-ray-amorphous form of silicon dioxide [37], It is manufactured in two steps. First, a silica hydrogel is formed b> means of a sol-gel process [38] (Section A.2.1.4) Secondly, the silica hydrogel is subjected to aftertreatment followed by dehydration to remove water. The product... 

Functionalization and solubilization of nanomaterials are important components of nanomaterials chemistry. A few of the articles in this section cover these aspects. Assembling nanomaterials is the subject matter of a few of the articles, while others deal with new techniques of preparing nanomaterials (e.g. hydrogel method). The use of the... 

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