User:Moira M. Esson/Notebook/CHEM-581/2013/03/22

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Objectives

  1. Finish last cycle of rapid freezing and subsequent thawing of the microspheres prepared on 2013/03/20
  2. Preparation of microspheres using PVA MW 130,000
  3. Run two-hour diffusion testing of microspheres with dye added.

Diffusion Testing

  • Diffusion testing was not able to be run. The caps were left on the microsphere samples and the water from the samples had not evaporated. The caps were removed from the samples. Diffusion testing will be completed next class.


Preparation of Microspheres

  • The general protocol for microsphere preparation described on 2013/02/20 and 2013/02/22.
  • The following preparations were run on a 0.05g scale as opposed to a 0.1g scale in case the 0.1g scale forms hydrogels. A comparison of the microspheres prepared on a different gram scale will be made.
  • A very small amount of PVA/clay was added to each vial and the vial was filled with safflower oil prior to the rapid freezing in order to achieve a true emulsion of microspheres in the organic safflower oil. This may prevent the formation of hydrogels.


PVOH vs. Clay Ratio Clay Selection PVOH 146K Mass (g) Actual Clay Mass (g) H2O Added (mL) Safflower oil added (mL)
50:50 NaMT 0.02530 0.02530 20 35
50:50 Laponite 0.02590 0.02500 20 35
90:10 NaMT 0.04140 0.01110 20 35
90:10 Laponite 0.04470 0.01100 20 35
50:50 110% CEC Laponite 0.02550 0.02500 20 35
90:10 110% CEC Laponite 0.04230 0.01150 20 35
50:50 50% CEC NaMT 0.02540 0.02500 20 35
90:10 50% CEC NaMT 0.04010 0.01050 20 35


Notes

  • Microspheres prepared with PVA 130,000 and PVA 146,000-186,000 will be prepared.
  • Microspheres prepared on 2013/03/20 seem to have formed small spheres and are easier to vortex as opposed to the previously prepared microsphere samples.