User:Samiye Yaman/Notebook/Lab 581/2013/02/20

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Contents

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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