- Prepare all polyvinyl alcohol(MW 146,000-186,000) hydrogels with clay additives
- Preparation of dye stock solutions.
Preparation of Hydrogels
- Using a clean 10mL-20mL beaker, add the desired amount of polyvinyl alcohol. (If preparing a 90:10 ratio of polyvinyl alcohol to clay hydrogel, add ~0.9g PVOH. If preparing a 50:50 ratio of polyvinyl alcohol to clay, ~0.5g polyvinyl alcohol should be added. All hydrogels were prepared on a 1g scale.)
- Add the desired amount of clay to the sample.
- Add a magnetic stir bar to the beaker and 6mL of distilled to the reaction mixture.
- Add 8wt% DMSO to the reaction mixture.
- Heat the reaction mixture to 80°C. If the reaction mixture begins to boil, immediately reduce heat.
- Allow the reaction mixture to stir at 80°C for at least 2 hours, or until complete dissolution of polyvinyl alcohol and equal distribution of clay throughout the reaction mixture.
- Remove reaction mixture from heat and place in freezer(-20°C) for 24 hours. After 24 hours, remove from the freezer and allow to thaw for 24 hours.
- Repeat this process three times.
The following procedure was adapted from PVA–clay nanocomposite hydrogels for wound dressing
- Need to add table of info
- Hydrogels containing sodium montmorillonite(NaMT) required the addition of 1mL distilled H2O and required longer heating time. This should be noted when dye is added. A separate, slightly more concentrated stock solution of dye should be prepared for addition to any hydrogels with NaMT additive.
- After preparation of 6 hydrogels, realized that the inclusion of dye will be necessary before the freeze-thaw crosslinking method is performed. I.e. Dye should be added during heating process of PVOH-clay reaction mixture.
Calcualtions for dye preparation