Activity coefficients of counterions and conformation in kappa‐carrageenan systems

Abstract

SynopsisThe optical rotation and the conductivity of kappa-carrageenans in aqueous solution have been investigated as functions of temperature in the presence of various electrolytes. The activity coefficients of sodium and potassium have been determined and correlated with the conformation. The potassium activity coefficient under ordered conformation is in agreement with a mechanism of dimerization.

Conformational change and aggregation of κ-carrageenan studied by flow field-flow fractionation and multiangle light scattering

“…9,13 -17 One coil r helix r rod r gel limitation to using SEC is the danger it involves that large-sized macromolecules or aggregates will be completely excluded or degraded. This can cause Certain cations (K / , Cs / , and Rb / ) 6 bind to a size-selective site 7 on the negatively charged kproblems for the k-carrageenan system since the distributions are usually very broad, and specifically carrageenan helix. Various anions such as I 0 likewise bind to the helix.…”

Thermodynamics of κ-Carrageenan–Amphiphilic Drug Interaction as Influenced by Specific Counterions and Temperature: A Microcalorimetric and Viscometric Study

“…However, there is ample evidence in the literature for the effect of specific counterions on the conformation of k-carraEffect of Drug Hydrophobicity on Interaction Energetics geenan (see e.g., Refs. (16)(17)(18)). …”

“…The measurements are made in the presence of excess of salts polymer is in the coil state in NaCl from Ç0ЊC upward and (Å30 mM); addition of even 0.4 mM AmitHCl is able to consequently shows a relatively smaller drop in cooperativ-perturb the structure. In the NaCl system, there is a shrinkage ity between 25 and 44ЊC (6,16,18).…”

Shaping of Gelling Biopolymer Drops in an Elongation Flow

“…The gel formation properties of carrageenan (13)(14)(15)(16) are strongly dependent on the type of carrageenan and the counterions present in the solution. The ion-dependence makes it possible to choose a suitable T gel by introducing the proper ions and ion strength with the solution.…”