Small-Angle Excess Scattering: Glassy Freezing or Local Orientational Ordering?

TL;DR

This study uses Monte Carlo simulations to investigate excess scattering in a dense polymer melt, revealing it stems from local nematic ordering rather than glass transition effects.

Contribution

The paper demonstrates through simulations that excess scattering in dense polymer melts is caused by local nematic order, not the glass transition, clarifying the origin of scattering signals.

Findings

Excess scattering correlates with local nematic order.

Glass-transition-like slowing-down occurs without direct relation to excess scattering.

Simulation evidence distinguishes between effects of nematic order and glass transition.

Abstract

We present Monte Carlo simulations of a dense polymer melt which shows glass-transition-like slowing-down upon cooling, as well as a build up of nematic order. At small wave vectors q this model system shows excess scattering similar to that recently reported for light-scattering experiments on some polymeric and molecular glass-forming liquids. For our model system we can provide clear evidence that this excess scattering is due to the onset of short-range nematic order and not directly related to the glass transition.