Dynamic Light Scattering Studies of Gelatin-Glutaraldehyde Complexes in Water

摘要

We report time resolved dynamic light scattering (TRDLS) measurements carried out on a system of aqueous gelatin [5% (w/v) i.e., above overlap concentration] solution cured with glutaraldehyde [3.0 × 10~(-3)% (w/v)] as a cross-linker, recorded at regular intervals of evolution time (i.e., from 5 min to 1440 min) following temperature quench from high temperature sol to low temperature gels as the system undergoes gelation. The experimentally obtained probe parameter-dynamic structure factor, S(q,τ)-deduced from the measured intensity correlation function, g_2(τ), incorporated appropriate allowance for the heterodyne contribution (often neglected in TRDLS analysis). Gelation threshold of the system, nearly 660 min after the temperature quench, has been obtained using parameters estimated from a non-linear regression of the deduced structure factor data. The temporal behaviour of different fit parameters (obtained from non-linear regression) linked to associated modes of relaxations in both the sol and gel states of the system, has been analyzed within the purview of well-defined theories capable to map this path of transition.