Rheological investigations, hydrogels

Caillard, R. Remondetto, G. E. Subirade, M. (2010) Rheological investigation of soy protein hydrogels induced by Maillard-type reaction. Food Hydrocol, Vol.24(l), 81-87. 

The internal dynamics of the physical hydrogels formed by hydrophobic associations was also investigated by rheological tests. In Fig. lOa-c, the elastic modulus, G (filled symbols), the viscous modulus, G" (open symbols), and the loss factor tan 5 G"IG lines) of HM PAAm hydrogels with and without SDS are... 

Ricciardi R, Gaillet C, Ducouret G, Lafuma F, Laupretre F (2003) Investigation of the relationships between the chain organization and rheological properties of atactic poly(vinyl alcohol) hydrogels. Polymer 44 3375... 

The rheological behavior of PMS suspensions was investigated to elucidate the influence of PMS concentration on interaction between particles. Diluted PMS hydrogel (i.e., suspension or colloidal solution) is characterized by the viscosity increasing with concentration (Figure 1.260a). 

Moreover, novel redox-responsive polycationic hydrogels of AAf-diethylacrylamide (DEAAm) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) were successfully synthesized by cross-linking reactions via quaternary ammonium compounds with a disulfide. The ability of the polymer netwoik to enclose and release substances by reductive cleavage or oxidative formation of disulfide bonds was shown exemplarily using different dyes. The redox-responsive character was proven by oscillatory rheological measurements and different material properties of polycationic polymer discs were also investigated. Because of its polycationic structure, this polymeric system could be a promising compound for complexation of DNA-like substances. Its ability for selective release in reductive environments, like tumor tissues, could possibly be used in medical applications or in chemotherapy [162]. 

The microdomain structure of novel two-phase hydrogels has been investigated using a variety of analytical techniques. It has been shown that these domains consist of side chains from the starting polymer which aggregate in such a way as to exclude water. In the presence of surfactant, these clusters incorporate surfactant monomer as well as side chain. The composition of these domains, specifically the number of side chains per cluster, influences the rheological properties of the networks. 

From a methodology point of view, the reological approach involves the investigation of the changes in rheological properties that mucoadhesive PE and hydrogels undergo when they are mixed with mucins. 

With this latter work, Meijer and coworkers introduced the first synthetic polymeric hydrogel based on supramolecular crosshnking of UPy-modified PEG. These materials are biodegradable, non-immunogenic, and tunable. In a followup publication, Meijer and coworkers investigated the rheological properties in greater detail and exploited this system further, primarily in view of application for protein delivery into kidneys [93]. 

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