User:Melissa Novy/Notebook/CHEM-581/2012/11/20

Objectives

• Run UV-vis on salt-exchanged PVOH(22K) + GA + PP films.

UV-Vis of Salt-Exchanged PVOH Films

• Protocol
  1. Place film in 20 mL 10 mM Fe₂(SO₄)₃.
  2. Time how long it takes for the film to change color from green to pink.
  3. Remove film from salt solution, pat dry with KimWipes, and cut with a 3.5 mm film cutter.
  4. Measure the thickness of the film with calipers, then place it in a quartz cuvette and take a spectrum from 200 nm to 800 nm.
  5. Place the film back in its H₂SO₄ solution.
  6. Discard the salt solution into a waste container.
  7. Repeat the above steps in 20 mL solutions of Al₂(SO₄)₃ and Na₂SO₄.
• The following films were analyzed with this protocol:
  • PVOH(22K) 1.0067 g + 1 mL GA + 1 mL PP + HCl
  • PVOH(22K) 1.0073 g + 1 mL GA + 1 mL PP
  • PVOH(22K) 1.05225 g + 0.5 mL GA + 1 mL PP
• Note that all films were stored in 2 wt% H₂SO₄ solution prior to being soaked in the salt solutions.
• Immediately after being placed in the three salt solutions, the PVOH(22K) 1.05225 g + 0.5 mL GA + 1 mL PP films became colorless.