Water uptake and transport studies in PVP-PMMA hydrogels
Wafa S., Sim L., Radzi Z., Yahya N., Kassim N., Rahman M., Czernuszka J., Arof A.
Hydrogels comprising 90 wt.% polyvinylpyrrolidone and 10 wt.% poly(methyl methacrylate) have been soaked in distilled water. By taking the mass change for different soaking times the number of water molecules entering the hydrogel can be calculated. A maximum in conductivity has been observed in the conductivity-soaking time plot. The increase and decrease in conductivity over time imply that some water molecules in the hydrogel are mobile (infrared band at 1598 cm-1) and immobile water band observed at 1687 cm-1. These can also be implied from the plot for number density of conductivity contributing water molecules versus soaking time. From the results shown water molecules diffuses at a faster rate when there are less conductivity contributing water molecules.