Discussion The FTIR spectra provide information about the functional groups of constituent polymers present in the cryogel. The spectra shown in Figure 1A and B indicate the presence of poly(vinyl) alcohol and savlon, as evident from the peaks observed at 3449 cm?1 and 3404 cm?1 respectively.29 The spectra (Fig. 1C) clearly mark a peak around 3683 cm?1, which is due to the overlapping peak selleckchem Imatinib of OH of PVA and NH2 group of chitosan.30 The IR spectra (Fig. 1C) also shows sharp peak around 1521 cm?1 (N-H bending) due to presence of CHX of savlon group.31 It is clear from the above discussion on the peaks that constituent polymers PVA and chitosan and savlon are present in the prepared cryogels. The effect of the PVA/chitosan wt. fraction on the extent of water sorption indicates that the swelling ratio increases when the PVA/chitosan wt.

fraction increases from 2.9 to 4.0, and thereafter the equilibrium swelling constantly decreases. Thus an optimum swelling is reached at a PVA/chitosan wt. fraction of 4.0. The results may be explained as below. The water sorption capacity of cryogels is also affected by the changing wt. fraction of PVA/chitosan contained in the cryogel. The results clearly show that water intake capacity constantly increases when the wt. fraction increases from 2.9�C4.0, while further increasing the wt. fraction results in a fall in the water sorption capacity. This clearly indicates that when the wt. fraction of PVA/chitosan is 4.0, the swelling becomes optimum. The observed findings may be explained as below.

Since both the constituents polymers, that is PVA and chitosan, are hydrophilic in nature, their increasing wt. fraction results in enhanced hydrophilicity of the matrix, which results in an increased water sorption capacity. However, beyond 4.0 wt. fraction of PVA, the water sorption capacity falls, which may be explained by the fact that when the PVA content is high and the resulting cryogel is enriched in crystalline region of PVA, this accounts for lower water sorption tendency of the cryogel. Similarly, when the wt. fraction of chitosan decreases from 12.1 to 4.0, the water intake capacity of the cryogels increases up to 4.0 wt. fraction, whereas a decrease in equilibrium swelling is noticed thereafter. The results may be attributed to the fact that chitosan is a cationic biopolymer, and its increasing content in the cryogel results in loosening of the network chains due to existing repulsion between the cationic chains of chitosan.

However, when the chitosan wt. fraction increases beyond 4.0, the network becomes densely crowed with the polymer chains, and water sorption capacity of the gel decreases. The presence of disinfectant savlon also affects the overall swelling ratio of the cryogel. It is observed that when the savlon content increases from 3 to 5 mL in the cryogel, Anacetrapib the swelling ratio also increases, whereas beyond 5mL of added savlon, a decrease in swelling ratio is observed.