User:Karlena L. Brown/Notebook/PVOH Research/2013/01/30

OBJECTIVES

• Begin preparing polyvinyl alcohol hydrogels for experimental analysis
• Prepare Rhodamine dye solutions for hydrogel dye attachments

90:10 PVOH Clay Hydrogel Preparations

1. In 10mL beaker, weigh out ~ 0.9 grams PVOH (MW 146K)
2. Then, using a graduated cylinder add ~ 6 mL H₂O to the beaker
3. After adding and combining PVOH (MW 146K) in a small beaker with H₂O, add a stir bar to stir solution
4. On hot plate, stir and heat beaker solutions at 70-80°C for ~ 1 hour or until PVOH dissolves
5. Once PVOH solids thoroughly dissolve in solution, then add ~ 0.1 gram of clay to the solution
6. Continue stirring the solution until a homogenous mixture forms and the clay is equally distributed
7. Allow the solution to cool to 40-50°C, and then remove the stir bar from the solution
8. Then place the solution into the freezer at -20°C to freeze for ~ 24 hours
9. The next day, remove the hydrogels in the freezer in order that the substances can thaw for ~ 24 hours
10. Continue the crosslinking freezing and thawing method for ~ 3 days

(Repeat entire process again when preparing hydrogels while using PVOH MW 130K samples)

50:50 PVOH Clay Hydrogel Preparations

1. In 10mL beaker, weigh out ~ 0.5 grams PVOH (MW 146K)
2. Then, using a graduated cylinder add ~ 6 mL H₂O to the beaker
3. After adding and combining PVOH (MW 146K) in a small beaker with H₂O, add a stir bar to stir solution
4. On hot plate, stir and heat beaker solutions at 70-80°C for ~ 1 hour or until PVOH dissolves
5. Once PVOH solids thoroughly dissolve in solution, then add ~ 0.5 gram of clay to the solution
6. Continue stirring the solution until a homogenous mixture forms and the clay is equally distributed
7. Allow the solution to cool to 40-50°C, and then remove the stir bar from the solution
8. Then place the solution into the freezer at -20°C to freeze for ~ 24 hours
9. The next day, remove the hydrogels in the freezer in order that the substances can thaw for ~ 24 hours
10. Continue the crosslinking freezing and thawing method for ~ 3 days

(Repeat entire process again when preparing hydrogels while using PVOH MW 130K samples)

90:10 Rhodamine 6G Dye Ratio Solution Preparation

1. In a small 50mL volumetric flask, pour in ~ 15mL of DMSO
2. Next weigh out ~0.22mg of Rhodamine 6G dye
3. Add and pour the dye solution into the 50mL volumetric flask containing DMSO
4. Lightly swirl flask to mix Rhodamine 6G dye with DMSO to form homogeneous mixture
5. Using a plastic pipette, pipette DMSO onto the weight boat to attain Rhodamine 6G residue left behind
6. Once all lost residue has be obtained, pour remaining remnants into the volumetric flask
7. Swirl periodically while filling flask with DMSO to the calibrated line

90:10 Rhodamine 6G Dye Ratio Calculations

 (0.900g PVOH) x (8/100) x (1/1.1008 g/mL (DMSO))= 0.0655mL
         M1V1 = M2V2
  1μM (RG6)x 6mL = (0.0655mL)M2    M2 = 92μM (RG6)
  92μM (RG6)(1x10-6M / 1μM RG6)(0.05L)(479.02g RG6 / 1 mole RG6)= 0.002g (RG6)

50:50 Rhodamine 6G Dye Ratio Solution Preparation

1. In a small 50mL volumetric flask, pour in ~ 15mL of DMSO
2. Next weigh out ~0.40mg of Rhodamine 6G dye
3. Add and pour the dye solution into the 50mL volumetric flask containing DMSO
4. Lightly swirl flask to mix Rhodamine 6G dye with DMSO to form homogeneous mixture
5. Using a plastic pipette, pipette DMSO onto the weight boat to attain Rhodamine 6G residue left behind
6. Once all lost residue has be obtained, pour remaining remnants into the volumetric flask
7. Swirl periodically while filling flask with DMSO to the calibrated line

50:50 Rhodamine 6G Dye Ratio Calculations

 (0.500g PVOH) x (8/100) x (1/1.1008 g/mL (DMSO))= 0.0364mL
         M1V1 = M2V2
  1μM (RG6)x 6mL = (0.0364mL)M2    M2 = 165μM
  165μM (RG6)(1x10-6M / 1μM RG6)(0.05L)(479.02g RG6 / 1 mole RG6)= 0.004g (RG6)

Important DMSO and Rhodamine 6G Safety

• Dimethyl Sulfoxide is toxic colorless liquid (MW: 78.13 g/mole)
• Rhodamine 6G is a toxic cancer linked pinkish black powder (MW: 479.02 g/mole)
• Avoid all dimethyl sulfoxide and rhodamine 6G skin contact by wearing gloves and googles
• Dimethyl Sulfoxide should be kept in the flammable cabinet when not in use
• Rhodamine 6G should be capped at all times when not in use to inhibit inhalation and free floating dust particles in the air
• When in use, dimethyl suloxide should be kept in the fume hood and rhodamine 6G should be used very carefully
• If spilled, wipe up dimethyl sulfoxide with paper towel while wearing gloves
• If spilled, wipe up rhodamine 6G residue first with paper towel soaked in cold water, then wipe over again with acetone while wearing gloves
• Keep all spills of dimethyl sulfoxide contained in the fume hood
• Keep all spills of rhodamine 6G in a closed space; rhodamine 6G contamination is easily transmitted through repeated glove or equipment contact
• Limit the contact of rhodamine 6G on uncontaminated surfaces or equipment by changing your gloves upon first contact with rhodamine 6G
• Wash hands after removing gloves that were in contact with dimethyl sulfoxide or rhodamine 6G

PVOH 146K Prepared Samples

Notes

• For the preparation of each hydrogel solution, exactly 6mL H₂O was used and placed in each beaker.
• Two different PVOH weights were used because higher PVOH molecular weights allowed for more contents such as clay to be encompassed into the hydrogels. Also higher molecular weight solutions crosslink using the freezing and thawing method a little better.
• Approximately an 8% weight solution of DMSO was prepared in order to finish making the dye solutions for tagging
• Five types of clay were used and prepared to be placed in the hydrogels: NaMT, Laponite, 110% CEC Laponite w/ 16 bromomethylhexyldecanoate, 110% CEC NaMT w/ 16 bromomethylhexyldecanoate, and 50% CEC NaMT w/ tributyl hexadecyl phosphonium bromide