Diffusion-viscosity decoupling in supercooled aqueous trehalose solutions.
The diffusional mobility of disodium fluorescein has been measured in supercooled aqueous solutions of trehalose, a widely used cryoprotectant disaccharide. The results were analyzed on the basis of the classical continuum hydrodynamic theory (Stokes-Einstein relationship) and compared with results for the diffusion and electrical conductivity of other ionic and nonionic solutes in trehalose and sucrose aqueous solutions. Disodium fluorescein obeys the classical model over a restricted range of inverse reduced temperatures, T g/ T, scaled by the glass transition temperature. Decoupling in neutral solutes takes place at higher values of T g/ T, while in ionic solutes it occurs all over the range of T g/ T studied, as observed for the water mobility in supercooled sugar solutions.
Corti
Horacio R
HR
Departamento Física de Materia Condensada, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Av. General Paz 1499, 1650 San Martín, Argentina. hrcorti@cnea.gov.ar
Frank
Guillermo A
GA
Marconi
Mario C
MC
D003080:Cold Temperature; D003451:Cryoprotective Agents; D004058:Diffusion; D044367:Phase Transition; D012996:Solutions; D014199:Trehalose / Q000737:chemistry*; D014783:Viscosity; D014867:Water / Q000737:chemistry*
D003451:Cryoprotective Agents; D012996:Solutions; D014867:Water; D014199:Trehalose