Macro- and micro-rheological properties of supercooled liquids could significantly contribute to the fundamental understanding of liquid state. To obtain pertinent data we studied the temperature resolved viscosity of ethylene glycol monohydrate, a binary mixture that exhibits hydrogen bonding and shows pronounced resilience to crystallization. In this work, we present the data related to macroviscosity obtained by measuring laminar flow in the temperature range of 40 to -70 0C. Below -70 0C the viscosity was determined by measuring the penetration rate of a cylindrical probe; a custom instrument was utilized for this purpose. The instrument’s design is such that the sample measured can be cooled to the desired temperature at a rate of 7 K/min or slower and turbidity and viscosity can be observed simultaneously. Ethylene glycol monohydrate exhibited strong deviation from Arrhenius behavior; it was found to be an even more fragile liquid than o-terphenyl. To assess the microviscosity of ethylene glycol monohydrate, the luminoprobe PRODAN was utilized. Upon excitation, its dipole moment increases by 5 D thus strongly affecting the solvation dynamics and resulting in a bathochromic fluorescence spectrum shift. The temperature resolved spectral shift showed that the water relaxation time at -85 0C is in order of 10 nanoseconds. Another luminoprobe, Ru(bpy)32+, that is sensitive to medium rigidity was utilized. The data obtained indicated that medium relaxation time is in order of microseconds at -100 0C.

Macro- and micro-rheological behavior of supercooled ethylene glycol monohydrate

2019 Spring National Meeting

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