User:Samiye Yaman/Notebook/Lab 581/2013/02/08

Objective

Description

Part A: pH study

*HCl solutions with different pH were prepared( pH 1.5, 2.5 & 3.5) in order to mimic the pH of stomach. Each hydrogels were left in the solution until wednesday.

• 30 ml of water added to the beaker. 0.18 g of PVOH with R6G(MW:146,00)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 1.5. (final pH=1.3)

• 30 ml of water added to the beaker. 0.16 g of PVOH with R6G(MW:146,00)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 2.5. (final pH= 2.29)

• 30 ml of water added to the beaker. 0.18 g of PVOH with R6G(MW:146,00)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 3.5. (final pH=3.3)

• 30 ml of water added to the beaker. 0.54 g of PVOH with R6G(MW:130,00)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 1.5.

• 30 ml of water added to the beaker. 0.56 g of PVOH with R6G(MW:130,00)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 2.5.

• 30 ml of water added to the beaker. 0.43 g of PVOH with R6G(MW:130,00)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 3.5.

• 30 ml of water added to the beaker. 0.58 g of PVOH with R6G(MW:89,000-98,000)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 1.5.

• 30 ml of water added to the beaker. 0.59 g of PVOH with R6G (MW:89,000-98,000)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 2.5.

• 30 ml of water added to the beaker. 0.60 g of PVOH with R6G (MW:89,000-98,000)(prepared on 30/01/2013) placed in to the beaker. Drops of 1M of HCl were added to the beaker until pH was close to 3.5.

Part B: swelling study

• Measure the mass of each hydrogel.

• Place the hydrogel in to a beaker with 20 ml of water.

• Masses of hydrogels before placing in to the water.

1)PVOH (MW:146,000) with R6G (prepared on 30/01/2013)=0.22g

2)PVOH (MW:130,000) with R6G (prepared on 30/01/2013)=0.66g

3)PVOH (MW:89,000-98,000) with (prepared on 30/01/2013)=0.55g

Data

Observation 1: PVOH with 22,000 molecular mass was still liquid after 3 cycles therefore it can be concluded that it might not be a good candidate for this research.

Observation 2: Photos of hydrogels

MW= 22,000g/mol(it was still liquid.)

MW=89,000 g/mol (most homogeneous hydrogel)

MW=130,000 g/mol (It was not homogenous. undissolved solids were visible in the hydrogel)

MW=146,000 g/mol (it was not homogenous. visible undissolved solids were present)

Notes

• Nanohydrogels are still going through their second cycle. Their cycle will end on 09/02/2013.