User:Moira M. Esson/Notebook/CHEM-581/2013/02/15

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Revision as of 16:26, 17 February 2013 by Moira M. Esson (talk | contribs) (Microsphere Preparation)
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Objectives

  1. Prepare PVA-clay microspheres.
  2. Run diffusion tests on hydrogels prepared on 2013/01/30 with Rhodamine 6G dye added on 2013/02/08.


Microsphere Preparation

  • Due to the relatively unsuccessful preparation of PVA/clay microspheres(the prepared spheres were either larger than a micrometer or did not appear at all), a new method was used for the preparation of PVA/clay microspheres.

General Protocol:

  1. The desired ratio of PVA and clay was measured out. The total mass was ~1g.
  2. The PVA/clay was placed in a 50mL beaker with a magnetic stir bar. 25mL distilled H2O were added to the beaker and the solution was heated to ~100°C and allowed to stir until complete dissolution of PVA/clay.
  3. The magnetic stir bar was removed and 25mL of mineral oil was added to the beaker.
  4. The contents of the beaker were poured into a blender to homogenize the solution and create an emulsion of the aqueous and organic layer in the attempt to create a suspension of microspheres.
  5. The blender was turned on a low setting for 5 minutes.
  6. The contents of the blender were poured into a beaker and the appropriate amount of DMSO/Rhodamine 6G solution was added.
  7. The microsphere solution was placed in a freezer at -20°C for 24 hours and then removed and allowed to thaw for 24 hours.
  8. Repeat this freeze-thaw cycle three times.

Preparation of Microspheres:

  • New calculations for the amount of DMSO/Rhodamine 6G to be added:

For a 90:10 ratio:

 (25mL)(1μM)/(92μM)=0.272mL

For a 50:50 ratio:

 (25mL)(1μM)/(165μM)=0.152mL
  • Information about prepared microspheres:
Prepared Clay-PVA(MW 146,000-186,000) microspheres ' ' ' '
Composition of hydrogel(ratio of PVA to clay) Amount of PVA added(g) Amount of clay added(g) Concencentration of DMSO/dye stock solution added(μM) Amount of DMSO/dye added(mL)
90:10 PVA:110% NaMT 0.9099 0.1045 92 0.272
50:50 PVA:110% NaMT 0.5076 0.4913 165 0.152
90:10 PVA:110% Lamponite 0.9010 0.0998 92 0.272


Observations:

  • After the addition of dye/DMSO to the 110% Lamponite, the dye appeared to stick to very small spheres at the bottom of the beaker. Bright pink spheres immediately formed. This did not occur for the samples containing 110% NaMT.


Fluorescence