User:Moira M. Esson/Notebook/CHEM-581/2012/11/16

Objectives

1. Standardize sodium bicarbonate solution
2. Run UV-vis on porphyrin films
3. Test swelling on all crosslinked glutaraldehyde films
4. Test the time necessary to facilitate a color change in various porphyrin using Fe₂(SO₄)₃ solution, Al₂(SO₄)₃ solution and Na₂SO₄.
5. Run UV-vis on color changed porphyrin films

UV-vis porhyrin films

General protocol for UV-vis on porphyrin films:

1. Remove crosslinked porphyrin films from deionized H₂O and pat dry using a paper towel
2. Using a quartz cuvette as a guide, cut a strip of paper the same width as the quartz cuvette.
3. Using the strip of paper as a guide and scissors(or a similar sharp instrument) carefully cut the porphyrin film the same width as the paper reference. When cutting the film, try and use a smooth portion of film.
4. Measure the thickness of the film. This will be used as the pathlength.
5. Using forceps, carefully place the cut strip of film in a clean quartz cuvette.
6. Using a spatula, gently press the film against the cuvette.
7. Carefully place the cuvette into the Shimadzu 2550 spectrophotometer.
8. Measure following the general protocol for UV-vis measurements

Porphyrin film UV-vis pathlengths:

Standardization of sodium bicarbonate

New weights of PHP used:

Titrations for sodium bicarbonate solution:

Acetylation

Titration information for acetylation:

• The general protocol for titrations was used. The sodium bicarbonate solution prepared2012/11/09 was used as the base. Three drops of bromothymol blue was added each PHP solution.

Swelling for GA films

General Protocol for film swelling:

1. Cut small piece of crosslinked glutaraldehyde films and place in small beaker. Allow to completely dry for ~48 hours
2. Weigh small piece of film. Record mass.
3. Place dry piece of film in 10mL beaker and add 10mL HPLC grade H₂O to completely cover the film. Parafilm the beaker and allow to sit for three days.
4. Reweigh the film. Record the mass.

Please refer to Melissa Novy's lab notebook for swelling information. Notes:

• Small pieces of film used for FTIR measurement were used for swelling information.
• All films experienced an increase in mass, which indicated the ability to reswell.
• Their was a noted difference between the swelling of films in which 0.5mL of GA was used as opposed to 1mL of GA. The crosslinking of 0.5mL GA did not inhibit swelling. In comparison, the crosslinking of the films in which 1mL GA was sufficient enough to inhibit swelling

Color Change of porphyrin films

General protocol for color change of porphyrin films:

1. Remove film from deionized H₂O and gently pat dry.
2. Cut film into 3 equivalent pieces
3. Place film pieces in 2 wt% H₂SO₄ until the film turns completely green
4. Remove film pieced from the H₂SO₄ and place the films into three separate beakers.
5. In each beaker add ~20mL of salt solution. (Each beaker will be filled with a different 10mM salt solution)
6. Once salt solution is added to the beaker, start a timer. Record the time that the film turns from green to pink.
7. Run UV-vis on the now pink films following the general protocol for UV-vis porphyrin films.

• Time neeeded to change the color of the film PVOH(22K) 1.0067g+1mL GA+1mL porphyrin

• UV-vis film information

Note: Two films that will be tested for color change were stored in 2wt% sulfuric acid. These films will undergo color change testing next time. The two films are:

1. 2.4394 PVOH(22K)+0.5mL GA+0.99mL porphyrine
2. 1.02114g PVOH(22K)+0.5mL+1mL porphyrine

Observations

• PVOH(22K) crosslinked GA+NaMT that was placed in Na₂SO₄ 2012/11/14 completely dissolved. The solution was very cloudy and almost had a powdery look.
• PVOH(22K) crosslinked GA+NaMT that was placed in CuSO₄ 2012/11/14 completely dissolved.
• PVOH(22K) crosslinked GA that were placed in Na₂SO₄ and CuSO₄ 2012/11/14 were completely intact. This indicates that surfactant clay promotes the dissolution of films in salt solution.