Computer simulations of the mechanism of thickness selection in polymer crystals

TL;DR

This paper uses computer simulations to critically evaluate and compare existing theories of polymer crystallization, leading to a new understanding of the mechanism behind lamellar thickness selection.

Contribution

It introduces a revised mechanism of thickness selection that differs from the Lauritzen-Hoffman and Sadler-Gilmer theories based on simulation analysis.

Findings

Computed free energy profile for nucleation of crystalline layers.

Analyzed a multi-pathway model with relaxed constraints.

Re-examined and challenged existing crystallization models.

Abstract

In this paper I describe the computer simulations that I have performed to critically examine the Lauritzen-Hoffman and the Sadler-Gilmer theories of polymer crystallization. In particular, I have computed the free energy profile for nucleation of a new crystalline layer on the growth face to compare with that assumed by the Lauritzen-Hoffman theory, I have analysed the mechanism of thickness selection in a multi-pathway model in which some of the constraints in the Lauritzen-Hoffman theory are relaxed, and I have re-examined the model used by Sadler-Gilmer. These investigations have lead to a mechanism of thickness selection of lamellar polymer crystals that differs from the two theories that I set out to examine.