Internal structures of agar-gelatin co-hydrogels by light scattering, small-angle neutron scattering and rheology.

摘要

Internal structures of agar-gelatin co-hydrogels were investigated as a function of their volumetric mixing ratio, [Formula: see text], 1.0 and 2.0 using dynamic light scattering (DLS), small-angle neutron scattering (SANS) and rheology. The degree of non-ergodicity (X = 0.2 ± 0.02), which was extracted as a heterodyne contribution from the measured dynamic structure factor data remained less than that of homogeneous solutions where ergodicity is expected (X = 10. The static structure factor, I(q), results obtained from SANS were interpreted in the Guinier regime (low-q, which implied the existence of ≈ 250 nm long rod-like structures (double-helix bundles), and the power law (intermediate-q regions) yielded I (q) ~ q(-α) with α = 2.3, 1.8 and 1.6 for r = 0.5, 1.0 and 2.0. This is indicative of the presence of Gaussian chains at low r, while at r = 2 there was a propensity of rod-shaped structures. The gel strength and transition temperatures measured from frequency sweep and temperature ramp studies were suggestive of the presence of a stronger association between the two biopolymer networks at higher r. The results indicate that the internal structures of agar-gelatin co-hydrogels were highly dependent on the volumetric mixing ratio.