Mean-square displacement relationship in bioprotectant systems by elastic neutron scattering.
Neutron intensity elastic scans on trehalose, maltose, and sucrose/H(2)O mixtures as a function of concentration, temperature, and exchanged wave vector are presented. The experimental findings show a crossover in molecular fluctuations between harmonic and anharmonic dynamical regimes. A new operative definition for the degree of fragility of glass-forming systems is furnished by using explicitly the connection between viscosity and mean-square displacement. The procedure is tested for the investigated mixtures and for a set of glass-forming systems. In this frame, the stronger character of trehalose/H(2)O mixture indicates a better attitude in respect to maltose and sucrose/H(2)O mixtures to encapsulate biostructures in a more rigid matrix.
Magazù
S
S
Dipartimento di Fisica and INFM, Università di Messina, Messina, Italy. smagazu@unime.it
Maisano
G
G
Migliardo
F
F
Mondelli
C
C
D001703:Biophysics / Q000379:methods; D004583:Electrons; D005898:Glass; D008320:Maltose / Q000737:chemistry; D008956:Models, Chemical; D015233:Models, Statistical; D009502:Neutrons; D012542:Scattering, Radiation; D013053:Spectrophotometry; D013059:Spectrum Analysis, Raman; D013395:Sucrose / Q000737:chemistry; D013696:Temperature; D014199:Trehalose / Q000737:chemistry; D014867:Water / Q000737:chemistry
D014867:Water; D013395:Sucrose; D008320:Maltose; D014199:Trehalose