Crossover in dynamics of polymeric liquids: Back to Tll?

✍ Scribed by A. Kisliuk; R. T. Mathers; A. P. Sokolov

• Book ID: 101351705
• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 184 KB
• Volume: 38
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/1099-0488(20001101)38:21<2785::aid-polb70>3.0.co;2-s

✦ Synopsis

Light scattering spectra of two polymers, polyisobutylene (PIB) and polystyrene (PS), were analyzed in the broad frequency range at temperatures above the glass transition (T g ). At high temperatures, the spectra followed the qualitative scenario suggested by mode-coupling theory (MCT) of the glass transition. The crossover temperature (T c ) was defined to be approximately 1.35 T g in PIB and approximately 1.15 T g in PS. At lower temperatures (T Ͻ T c ), the light scattering spectra deviated strongly from the idealized MCT scenario. Different signs of the dynamic transition around T c are discussed. The difference between the suggested interpretation and an old idea of the liquid-liquid transition in polymeric liquids is stressed: we describe the transition as purely dynamic in nature.