Objections
Description
Part 1
- Prepare 3 sets of hydrogels with phosphate buffers
A)0.51 g of PVOH (MW:89,000-98,000) with 4 ml of phosphate buffer was placed on to a heat block at 100C.
B)0.25 g of PVOH (MW:89,000-98,000) with 3 ml of phosphate buffer was placed on to a heat block at 100C.
C)0.14 g of PVOH (MW:89,000-98,000) with 3 ml of phosphate buffer was placed on to a heat block at 100C.
- Homoginize each of the hydrogels solutions with 35 ml of safflower oil. Right after pouring in to a beaker, flash freeze it with liquid nitrogen then place them into freezer. (3 freeze thaw cycle, 20 hours freeze 4 hours room temperature)
Part 2
- Prepare 3 sets of hydrogels with phosphate buffers
A)0.52 g of PVOH (MW:89,000-98,000) with 4 ml of phosphate buffer was placed on to a heat block at 100C.
B)0.25 g of PVOH (MW:89,000-98,000) with 3 ml of phosphate buffer was placed on to a heat block at 100C.
C)0.13 g of PVOH (MW:89,000-98,000) with 3 ml of phosphate buffer was placed on to a heat block at 100C.
- Homoginize each of the hydrogels solutions with 50 ml of safflower oil. Pour them in to a petri dish to have a larger surface area then place them into freezer.(-20C) (3 freeze thaw cycle)
Part 3
- Prepare a set of hydrogel with phosphate buffer
A)0.25 g POVH (MW:89,000-98,000) with 4 ml of phosphate buffer was blaced to a heat block at 100C.
- Homoginize each of the hydrogels solutions with 50 ml of mineral oil. Pour them in to a petri dish to have a larger surface area then place it into the freezer.(-20C) (3 freeze thaw cycle)
Data
Notes
- Safflower oil was used instead of mineral oil. Safflower oil has lower freezing point (approximately -17) than mineral oil (fp:-30C)
The reason why we wanted to try safflower oil was it has freezing point lower than -20C. Mineral oil did not freeze completely at -20C.
- We used big petri dishes instead of beakers to increase the surface area and have a less dense medium as hydrogels sink at the bottom of the container. (to observe if larger surface area will make any difference)
- Liquid nitrogen was used to flash freeze the hydrogels before they sink at the bottom of the container.
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