The Flory-Huggins interaction parameter χgel was determined for chemically crosslinked poly(vinyl alcohol) (PVA) hydrogels from swelling pressure and elastic modulus measurements. The PVA gels were prepared in aqueous solutions of different molecular weight (22 000 < Mw < 346 000). Crosslinks were introduced at different polymer concentrations (3% w/w ≤ c0 ≤ 12% w/w). It is found that in all systems the values of χgel for the crosslinked polymer are greater than the values of χsol for the uncrosslinked material at identical concentrations. The χgel data reported here seem to be a function only of the polymer concentration and are independent of the details of the network structure. The results are discussed in relation to other work on the crosslink dependence and volume fraction dependence of χgel.
- PVA hydrogels