Characterization of hydrogels

Hydrogels are water-containing polymers, hydrophilic in nature, yet insoluble. In water, these polymers swell to an equiUbrium volume and maintain thek shape. The hydrophilicity of hydrogel is a result of the presence of functional groups such as —NH2, —OH, —COOH, —CONH2, —CONH—, —SO H, etc. The insolubihty and stabiUty of hydrogels are caused by the presence of a three-dimensional network. The scope, preparation, and characterization of hydrogels has been reviewed (107). 

Characterization of Hydrogel Films. Mechanical testing was conducted in buffered saline on an Instron instrument, according to the modified ASTM D-1708 (tensile) and D-1938 (tear) and were reported in g/mm2 for modulus and g/mm for tear strength. The water contents and the amount of extractables were measured gravimetr ica1ly. 

Liu RH, Yu Q, Beebe DJ (2002) Fabrication and characterization of hydrogel-based microvalves. J Microelectromech Syst 11 45-53... 

S. Rammensee, D. Huemmerich, K.D. Hermanson, T. Scheibel, A.R. Bausch, Rheological characterization of hydrogels formed by recombinanfly produced spider silk, Appl. Phys.A Mater. Sci. Process. 82 (2006) 261-264. 

Martens P, Anseth KS. Characterization of hydrogels formed from acrylate modified poly(vinyl alcohol) macromers. Polymer 2000 41 7715-7722. 

Johnson BD, Baner JM, Niedermaier DJ, Crone WC, Beebe DJ (2004) Experimental techniques for mechanical characterization of hydrogels at the microscale. Experim Mech 44 21-28 10. Kraft ML, Moore JS (2003) n-Alkyl fatty acid modified microgels ton permeation as a function of chain length. Langmuir 19 910-915... 

H. Sokker, A. Abdel Ghaffar, Y. Gad, and A. Aly, Synthesis and characterization of hydrogels based on grafted chitosan for the controlled drug release. Carbohydrate Polymers, 75 (2), 222-229, 2009. 

Hydrogels are water-swollen, crosslinked polymeric structures produced by the simple reaction of one or more monomers, or by association bonds such as hydrogen bonds and strong van der Waals interactions between chains [1]. Hydrogels have received significant attention, especially in the last twenty-eight years, because of their exceptional promise in biomedical applications. The classical book of Andrade [2] offers some of the best work that was available prior to 1975. The more recent book by Peppas [1] as well as several review articles [3-7] address the preparation, structure, and characterization of hydrogels. 

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