Phase behavior of agarose in binary solvents

The thermoreversible gelation of agarose has been investigated in four different aqueous binary solvents: water/dimethyl sulfoxide, water/N,N-dimethylformamide, water/N-methylformamide, and water/formamide. The thermal behavior through the gelation/melting temperatures and the gelation/melting enthalpies has been studied, and phase diagrams have been subsequently established as a function of agarose concentration and solvent composition. The elastic modulus has been determined as a function of the same parameters. The results are discussed by considering different possible models. It is suggested that agarose/water/cosolvent ternary complexes can account for the experimental results.