General Properties of Hydrogels

The cross-linking density cannot be estimated from the stoichiometric relation between monomer and cross-linker, e.g., NlPAAm and MBAAm, since the possibility of cychzation during NlPAAm polymerization is high (see Sect. 2, in chapter General properties of hydrogels ). A more realistic number of net chains can be determined by compression or stress-strain measurements, preferred on a gel swollen in organic solvent. 

Sometimes it could be useful to discuss the influence of swelling as dependencies on the ratio of the current gel volume and the volume after the chemical synthesis of the gel (see Sect. 2 in chapter General properties of hydrogels , normalized gel volume). 

Okay O (2009) General properties of hydrogels. In Gerlach G, Arndt K-F (eds) Hydrogel sensors and actuators, Springer series on chemical sensors and biosensors, vol 6. Springer, Berlin, pp 1-14... 

Dumitriu, S. and C. Dumitriu-Medvichi, Hydrogel and general properties of biomaterials, in S. Dumitriu, Polymeric Biomaterials. New York Marcel Dekker, 1994, pp. 3-97. 

Enzyme-responsive polymers can be classified in various ways, for example according to their structure, function or response type or mechanism. Here, we classify enzyme-responsive polymers, according to their structural elements, into polymer hydrogels, supramolecular polymers, polymer particles and self-immolative polymers. The general properties of these classes and their importance in biomaterial apphcations will be introduced. Using examples from the recent literature, we will demonstrate how enzyme responsiveness can be incorporated into these materials. 

The general properties of oil-separation sheets are shown in Table 3. The A test described in the table is the test method developed by the authors (see Fig. 3). This method evaluates the oil-water separation sheets by how much an oil droplet placed on top of the wet sheet permeates the sheet. If there is no hydrogel included, the oil spreads throughout the surface. Thus, it is possible to estimate qualitatively the oil-water separation by observing the remaining state of the oil droplet. 

In general, we determine the magnitude of pzc and iep by electrophoretic or potentiometric titration methods. In some cases, these data have been obtained by using the streaming potential measurements. In a recent stndy, the wetting properties of silanated surfaces were investigated by AFM. Also, the force measnrement on hydrogel was measured by AFM. ... 

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