User:Karlena L. Brown/Notebook/PVOH Research/2013/02/15: Difference between revisions

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* Prepare new microsphere samples using new method of preparation
* Prepare new microsphere samples using new method of preparation


==New Method PVOH Clay Microsphere Preparations==
==New Method of PVOH Clay Microsphere Preparations==
# In 50mL beaker, dissolve ~ 1.0g total of PVOH 146K or PVOH 130K along with clay additive selected in 25mL hot deionized H<sub>2</sub>O
# In 50mL beaker, dissolve ~ 1.0g total of PVOH 146K or PVOH 130K along with clay additive selected in 25mL hot deionized H<sub>2</sub>O
# Place a stir bar in the 50mL beaker and then heat solution at 100°C for ~ 12-15 minutes until complete dissolution of PVOH / clay sample
# Place a stir bar in the 50mL beaker and then heat solution at 100°C for ~ 12-15 minutes until complete dissolution of PVOH / clay sample

Revision as of 22:51, 24 February 2013

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OBJECTIVES

  • Continue to run fluorescence testing on samples containing Rhodamine 6G dye
  • Prepare new microsphere samples using new method of preparation

New Method of PVOH Clay Microsphere Preparations

  1. In 50mL beaker, dissolve ~ 1.0g total of PVOH 146K or PVOH 130K along with clay additive selected in 25mL hot deionized H2O
  2. Place a stir bar in the 50mL beaker and then heat solution at 100°C for ~ 12-15 minutes until complete dissolution of PVOH / clay sample
  3. Cool solution for ~ 5 minutes, then remove the stir bar, and then add 25mL of mineral oil to the sample
  4. Place sample solution prepared in a blender to form a more homogeneous mixture / emulsion (creating a suspension of microspheres)
  5. Allow blender to stir at low settings for 7 minutes
  6. After 7 minutes, add some Rhodamine 6G dye to the solution based upon the ratio selection (90:10 vs. 50:50)
  7. After the addition of dye, allow the solution to go through freeze / thaw crosslinking process for ~ 2-3 days
  8. Place microsphere solution in a freezer at -20°C for 24 hours and then remove and allowe to thaw for 24 hours


Reference: http://www.sciencedirect.com/science/article/pii/S0168365998000893

PVOH 146K Prepared Samples & Dye Preparations

1μM Rhodamine 6G Dye Concentration

  M1V1 = M2V2
  1μM (RG6)x 25mL = (92μM)V2    V2 = 271.74μL

1μM Rhodamine 6G Dye Concentration

  M1V1 = M2V2
  1μM (RG6)x 25mL = (165μM)V2    V2 = 152.00μL
PVOH vs. Clay Ratio Clay Selection PVOH 146K Mass (g) Actual Clay Mass (g) H2O Added (mL) Dye Concentration (μM) Dye Amount Added (μL)
50:50 110% CEC NaMT w/ DMHXLBR 0.50760 0.49130 25 165 152
90:10 110% CEC NaMT w/ DMHXLBR 0.90990 0.10450 25 92 272
90:10 110% CEC Laponite w/ DMHXLBR .90100 0.09980 25 92 272

Notes

  • Hydrogels that completed the freeze / thaw cycle which had ~ 4mL of H2O added in order for fluorescent analysis include:
  # 50:50 PVOH 130K 110% CEC NaMT w/ DMHXLBR
  # 90:10 PVOH 130K 110% CEC Laponite w/ DMHXLBR
  # 50:50 PVOH 130K 110% CEC Laponite w/ DMHXLBR
  # 90:10 PVOH 130K 110% CEC NaMT w/ DMHXLBR
  • For fluorescence analysis, samples were taken every 15 minutes for 2hrs to determine a dye leaching / diffusion rate from hydrogels
  • Fluorescent samples run and completed for 2hr diffusion rate determinations:
  # Hydrogel 50:50 PVOH 146K 50% CEC NaMT w/ Bu3HdP+
  # Hydrogel 90:10 PVOH 146K 50% CEC NaMT w/ Bu3HdP+
  # Hydrogel 50:50 PVOH 146K NaMT
  # Hydrogel 90:10 PVOH 146K NaMT
  # Hydrogel control PVOH 146K 
  # Hydrogel 90:10 PVOH 146K Laponite
  • In regards to the spectra, all samples maintained a quick diffusion rate indicating that dye crosslinking during the freeze / thaw cycle is pertinent when making hydrogels because it slows down the diffusion rate
  • For the hydrogels in which the dye was added, but not crosslinked into the material, their diffusion rate was the quickest -- a significant amount of dye leaked out of those hydrogels throughout the 2 hour period
  • Comparing the 50:50 vs. the 90:10 ratio of PVOH / clay, the hydrogels with 50:50 ratio had more dye leak out than the 90:10 ratio hydrogels indicating a more effective pressure stimuli