1. Role of microscopic phase separation in gelation of aqueous gelatin solutions.
- Author
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Pelc D, Marion S, Požek M, and Basletić M
- Subjects
- Dielectric Spectroscopy, Diffusion, Gels chemistry, Solutions, Water chemistry, Gelatin chemistry
- Abstract
Using a unique home-made cell for four-contact impedance spectroscopy of conductive liquid samples, we establish the existence of two low frequency conductivity relaxations in aqueous solutions of gelatin, in both liquid and gel states. A comparison with diffusion measurements using pulsed field gradient NMR, and circular dichroism spectroscopy, shows that the faster relaxation process is due to gelatin macromolecule self-diffusion. This single molecule diffusion is mostly insensitive to the macroscopic state of the sample, implying that we have a clear separation of gelatin molecules into a free and network-bound phase. Scaling relationships for the self-diffusion indicate that the gelation process is not a percolative phenomenon, but is caused by aggregation of triple helices into a system-spanning fibre network.
- Published
- 2014
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