NMR Imaging: Monitoring of Swelling of Environmental Sensitive Hydrogels

Cross-linked hydrophilic polymers immersed in water can uptake the water. They swell and form hydrogels. The improved performance of hydrogels in biological systems is strongly associated with the water content in the polymeric system. The swelling process is critical to technology areas such as chemical industry (separation matrices), medicine and medical care (gels for cell culture, soft contact lenses, and drug delivery), sanitary products (superabsorbent gels), farming and agriculture (superabsorbend polymer-mixed soil), electric and electronic industries (electrolyte gel), and sensors (fixation of enzymes onto gel) [1]. The kinetic of swelling determines time-constants of the processes using the uptake or loss of swelling agent. The water transport mechanism into the polymer is particularly important for assessing the suitability of hydrogels as drug delivery and drug release systems, as the amount of released drug is dependent on the rate and the transport mechanism of water diffusing into the gel.