Thermally-Sensitive Hydrogels

This section is principally devoted to the preparation of thermally sensitive hydrogel particles using the batch polymerization process. The effect of each reactant and parameter (initiator, temperature, cross-linker agent) on the polymerization process (polymerization kinetic, conversion, final particle size, morphology, water-soluble polymer, etc.) is presented and discussed. For the... 

Because the adsorption of proteins onto such thermally sensitive particles is salinity and pH dependent, the adsorption can be assumed to be governed principally by electrostatic interactions rather than hydrophobic adsorption process as generally reported. In any case, in view of these results, the driving forces in adsorption of proteins onto thermally sensitive hydrogel particles are debatable, and further research is necessary to demonstrate the driving forces involved in the adsorption process. 

Hoffmann J, Plotner M, Kuckling D, Fischer W-J (1999) Photopatteming of thermally sensitive hydrogels useful for microactuators. Sens Actuat 77 139-144 Houbenov N, Minko S, Stamm M (2003) Mixed polyelectrolyte brush from oppositely charged polymers for switching of surface charge and composition in aqueous environment. Macromolecules 36 5897-5901... 

Intelligent gels Thermally sensitive hydrogels Thermosensitive hydrogels... 

Figure 2.12 Thermal sensitive hydrogels of poly(N-isopropyl acrylamide) (PNIPAm).

Thermally-sensitive hydrogels were also used as dehydration reagents. In this case, the water absorption and desorption is led in the proximity of phase-transition temperature of used gels. Polymer gels based on N-isopropylacrylamide have been used for concentrating albumin, gelatine or dextrane solutions [135]. 

I. El-Sherbiny, E. Abdel-Bary, and D. Harding, Swelling characteristics and in vitro drug release study with pH-and thermally sensitive hydrogels based on modified chitosan. Journal of Applied Polymer Science, 102 (2), 977-985,2006. 

Q. Zhou, L. Zhong, X. Wei, W. Dou, G. Chou, and Z. Wang, Baicalein and hydroxypropyl-y-cyclodextrin complex in poloxamer thermal sensitive hydrogel for vaginal administration, Int. J. Pharm., 454 (1), 125-134,2013. 

Using such process and such batch radical polymerization process, various thermally sensitive hydrogels have been elaborated using NIPAM, NIPMAM, NEMAM, and more recently A-vinyl caprolactam (VCL)-based microgels [7-10]. 

In view of these results, the driving forces in the adsorption of proteins onto thermally sensitive hydrogel particles are debatable, and further research is necessary in order to demonstrate the driving forces involved in the adsorption process. 

Thermosensitive hydrogels Thermally-sensitive hydrogels Intelligent gels... 

Gilchrist, R, et al. The precorneal residence of a thermally sensitive hydrogel. In 137th British Pharmaceutical Conference Scarborough (1997)... 

Reprinted from Sensors and Actuators A, Physical 77, J. Hoffmann, M. Plotner, D. Kuckling, W.-J. Fischer, Photopatteming of thermally sensitive hydrogels useful for microactuators , 139-144, 1999, with permission from Excerpta Medica Inc. 

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