Hydrogel Swelling Essay

3. Results and discussion
3.1 Swelling studies
The swelling behavior of the hydrogel and silver nano composite hydrogel were investigated with two distinct ways: a)versus PEG/ Chitosan ratio at constant crosslinker(MBA) amount(0.1 g.), b)versus various MBA amount at constant PEG/Chitosan ratio(0.2/1, g/g.).
The swelling capacity decreased by addition of PEG in the preparation of hydrogels. This can be attributed as the additional PEG chains are well dispersed in the hydrogel network leading to increase in the apparent crosslink density and it is known that addition of crosslink density decrease the swelling capacity as shown in Figure 1 7. After preparing AgNP inside hydrogel network, bulk properties of hydrogel have changed in compared to pure hydrogel which is contributed to chemical environment network changes resulting from AGNPs 11. The hydrogel swelling behaviour is completely influenced by variation in crosslink density such that by increasing the MBA

Another peak at 1641 cm-1 (1650 cm-1 for Ag-loaded) is related to metal absorption by functional group (amid I) NHCOCH3- , 1531 for amid II stretching and1316 cm-1 for N-H stretching 17. These hydroxyl groups are ideal sites for connection and strengthen AgNPs so they help nano silver stability after particle formation. Results showed that the synthesishydrogel revealed a good compability between chitosan and PEG with significant changes after silver nanoparticle formation. Silver nanoparticles. Peak 3336 to 3434, 1641 to 1654, and 1316 to 1384 transferred which indicates good compability between chitosan and PEG that increases after silver nanoparticles formation. This restrictly confirmed that formation of AgNPs leads to increase in elongation of the main polymer chains, resulting in increasing flexibility as pointed out in swelling