To crosslink PVOH/glutaraldehyde and PVOH/PDMS/glutaraldehyde films, make a 1 g PVOH/glutaraldehyde film, make additional standards, and finish clay-CuSO4 exchange (from 9/26).
Crosslinking Glutaraldehyde Films
- Allow the PVOH film containing glutaraldehyde to dry completely.
- Prepare a solution of 100 mL H2O, 2 mL concentrated H2SO4, and 20 g Na2SO4 in a 150 mL beaker. (solution is referred to as glutaraldehyde fixant)
- Place stir bar in beaker and a Buchner funnel top (cap) over the stir bar
- Heat solution to 70°C (temperature on hotplate should be about 160)
- Place film in solution for one hour.
- Prepare 100 mL of a 1% HCl solution in a 150 mL beaker. Place a stir bar and an inverted buchner funnel into beaker.
- Heat HCl solution to 70°C
- Remove film from glutaraldehyde fixant and rinse with distilled water.
- Place film into HCl solution for 30 minutes.
- Prepare 0.2 M sodium bicarbonate solution. (1.68 g in 100 mL)
- After 30 minutes, remove the film from the HCl solution and place into the sodium bicarbonate solution (at room temperature) for about 15 minutes.
- Use tweezers to remove the film from the sodium bicarbonate solution.
- Rinse film with deionized water and place in a beaker with distilled water until it is used.
Making a 1 g PVOH/glutaraldehyde film
- 1 g of PVOH was weighted out and dissolved in 6 mL of water in a small beaker with a stir bar.
- The beaker was placed on a hotplate and was heated to allow the PVOH to dissolve into the water.
- 1 mL of glutaraldehyde was added to the PVOH.
- The solution was stirred under the fume hood for 5 minutes.
- Because the solution thickened too much (see notes section), it was not poured into a plastic dish and will be remade on 10/3/12
- 0.4 g PVOH and 0.1 g PDMS were dissolved in 5 mL of water on a hot plate.
- Once dissolved, 1 mL of glutaraldehyde was added to the PVOH/PDMS
- The mixture was allowed to stir without heat for 3 minutes
- The film was poured into a dish and was left under the hood over the weekend
Clay-Copper Sulfate Exchange
- Three samples, each with 0.1 g of clay was measured out for the Na-MT, 100% CEC, 50% CEC, and Na-MT coated iron oxide
- Each sample was placed in 10 mL of copper sulfate solution that was previously prepared.
- The samples were stirred in the copper sulfate for either 1, 5, or 10 minutes.
- The samples were then filtered. Both the filtrate and the filter paper were saved.
No data was collected today.
- When making the 1 g PVOH/glutaraldehyde film, after the glutaraldehyde was added the solution thickened to the point that the stir bar could no longer stir. The solution was reheated to see if it would thin, but it did not.
- When conducting the exchange using the iron, during the filtering of the 10 minute sample, some of the iron passed through the filter.