Identification of finite shear-elasticity in the liquid state of molecular and polymeric glass-formers

Abstract

Finite shear elasticity has been identified in the liquid state. The study is expanded to a van der Waal's molecular glass-former, o-terphenyl, and to an ordinary polymer melt, polybutylacrylate, as a function of their molecular weight. These fluids exhibit shear elasticity at the sub-millimetre scale and far above any phase transition. This macroscopic property challenges the conventional terminal relaxation modes (α-process or terminal viscoelastic times (reptation)) in terms of individual molecular process.

Keywords:

• glass formers
• liquid state
• elastic properties

Acknowledgements

The authors are grateful to the Veeco Society for providing high resolution AFM photographs of the alumina substrates.