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