Jose Navya Mary, Nicolai Taco, Renou Frédéric, Benyahia Lazhar
IMMM UMR CNRS 6283, Le Mans Université, France.
IMMM UMR CNRS 6283, Le Mans Université, France.
Carbohydr Polym. 2025 Oct 15;366:123879. doi: 10.1016/j.carbpol.2025.123879. Epub 2025 Jun 9.
The gelation behaviour of κ-carrageenan (κ-car) in the presence of KCl was examined in binary mixtures with dextran (Dex) or polyethylene oxide (PEO), as well as in water-in-water (W/W) emulsions formed by these polymers. The results show that the presence of Dex or PEO has only a weak effect on κ-car gelation. However, it affects the microstructure rendering the κ-car network more homogenous with increasing viscosity of the DEX or PEO solutions. In the W/W emulsions, κ-car preferentially partitioned to the Dex-rich phase. Rheological measurements showed that the storage modulus (G') increased with the volume fraction of the PEO phase (φ) as long as the Dex phase was continuous. The transition of the DEX phase from continuous to dispersed at φ ≈ 70 % resulted in a sharp reduction of the gel stiffness. Weak gels were nevertheless formed up to φ ≈ 80 % due to aggregation of gelled Dex droplets into a system spanning network. For φ > 90 %, G' increased again sharply as an increasing fraction of the κ-car partitioned to the PEO phase. This work highlights that the rheology of W/W emulsions can be tuned by adding κ-car.
研究了κ-卡拉胶（κ-car）在KCl存在下与右旋糖酐（Dex）或聚环氧乙烷（PEO）二元混合物中的凝胶行为，以及由这些聚合物形成的水包水（W/W）乳液中的凝胶行为。结果表明，Dex或PEO的存在对κ-car凝胶化的影响较弱。然而，它会影响微观结构，随着DEX或PEO溶液粘度的增加，使κ-car网络更加均匀。在W/W乳液中，κ-car优先分配到富含Dex的相中。流变学测量表明，只要Dex相是连续的，储能模量（G'）就会随着PEO相的体积分数（φ）增加。当φ≈70%时，DEX相从连续相转变为分散相，导致凝胶刚度急剧降低。然而，由于凝胶化的Dex液滴聚集形成跨越系统的网络，在φ≈80%之前仍会形成弱凝胶。对于φ>90%，随着越来越多的κ-car分配到PEO相中，G'再次急剧增加。这项工作突出了通过添加κ-car可以调节W/W乳液的流变学。
