Hydrogels: Hydrogels: Special PolymersSpecial Polymers
Examples of HydrogelsExamples of Hydrogels
http://www.robaid.com/wp-content/gallery/medicine-1/hydrogel-lenses-could-help-diabetics.jpg
Contact lenses
http://www.womansday.com/var/ezflow_site/storage/images/wd2/recipes/tutti-frutti-gelatin-mold/190937-1-eng-US/tutti-frutti-gelatin-mold_slideshow_image.jpg
Gelatin
http://www.medgadget.com/archives/img/hydron_sm.jpg
Drug deliveryhttp://www.foryoumedical.com/UserFiles
%5C49%5C20090710%5C79B26D5DD2D17DAB749FBA4D529D0293.jpg
Wound dressing
http://www.stevespanglerscience.com/img/cache/bcb9b8db117ee64376aedaf7af3595ca/water-jelly-crystal-flower.jpg
Soil moistener
Sodium alginateSodium alginate One of the components of the hydrogel One of the components of the hydrogel
that will be synthesizedthat will be synthesized Long chain polymer – covalently bondedLong chain polymer – covalently bonded Sodium ions (Na+) ionically bonded to Sodium ions (Na+) ionically bonded to
chainchain
http://www.aapspharmscitech.org/articles/pt0803/pt0803072/pt0803072_figure1.jpg
CrosslinkingCrosslinking
Sometimes bonds can Sometimes bonds can form between long form between long chain polymerschain polymers
Forms a network Forms a network structurestructure
Referred to as Referred to as crosslinked polymerscrosslinked polymers
CrosslinkingCrosslinking
http://www.emeraldinsight.com/content_images/fig/2180130305001.png
CrosslinkingCrosslinking
How is the crosslinking in this example different How is the crosslinking in this example different from the crosslinking in the previous example?from the crosslinking in the previous example?
http://wiki.chemprime.chemeddl.org/images/9/97/Cross-Linked_Polymer.jpg
CrosslinkingCrosslinking
How is the crosslinking in this example different How is the crosslinking in this example different from the crosslinking in the previous example?from the crosslinking in the previous example?
http://wiki.chemprime.chemeddl.org/images/9/97/Cross-Linked_Polymer.jpg
HydrogelsHydrogels
Crosslinked polymersCrosslinked polymers Can trap large quantity of Can trap large quantity of
water in the network water in the network structure (“hydro”)structure (“hydro”)
Shrink when driedShrink when dried
HydrogelsHydrogels