scholarly journals Property Decoupling across the Embryonic Nucleus–Melt Interface during Polymer Crystal Nucleation

2020 ◽  
Vol 124 (23) ◽  
pp. 4793-4804
Author(s):  
Kyle Wm. Hall ◽  
Simona Percec ◽  
Wataru Shinoda ◽  
Michael L. Klein
Keyword(s):  
Crystal Nucleation ◽  
Polymer Crystal

scholarly journals Monodisperse Polymer Melts Crystallize via Structurally Polydisperse Nanoscale Clusters: Insights from Polyethylene

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 447 ◽  
Author(s):  
Kyle Wm. Hall ◽  
Timothy W. Sirk ◽  
Simona Percec ◽  
Michael L. Klein ◽  
Wataru Shinoda
Keyword(s):  
Large Scale ◽  
Polymer Melts ◽  
Polymeric Materials ◽  
Crystalline Polymer ◽  
Crystal Nucleation ◽  
Stem Length ◽  
Polymer Crystal ◽  
Polyethylene Melts ◽  
Nanoscale Clusters ◽  
Entangled Polymer Melts

This study demonstrates that monodisperse entangled polymer melts crystallize via the formation of nanoscale nascent polymer crystals (i.e., nuclei) that exhibit substantial variability in terms of their constituent crystalline polymer chain segments (stems). More specifically, large-scale coarse-grain molecular simulations are used to quantify the evolution of stem length distributions and their properties during the formation of polymer nuclei in supercooled prototypical polyethylene melts. Stems can adopt a range of lengths within an individual nucleus (e.g., ∼1–10 nm) while two nuclei of comparable size can have markedly different stem distributions. As such, the attainment of chemically monodisperse polymer specimens is not sufficient to achieve physical uniformity and consistency. Furthermore, stem length distributions and their evolution indicate that polymer crystal nucleation (i.e., the initial emergence of a nascent crystal) is phenomenologically distinct from crystal growth. These results highlight that the tailoring of polymeric materials requires strategies for controlling polymer crystal nucleation and growth at the nanoscale.

scholarly journals Polymer Nucleation under High-Driving Force, Long-Chain Conditions: Heat Release and the Separation of Timescales

2018 ◽  
Author(s):  
Kyle Hall ◽  
Simona Percec ◽  
Michael Klein
Keyword(s):  
Conformational Changes ◽  
Driving Forces ◽  
Early Stage ◽  
Polymer Crystallization ◽  
Crystal Nucleation ◽  
Crystal Formation ◽  
Polymer Crystal ◽  
Dynamics Simulations ◽  
New Research ◽  
Chain Level

<p>This study reveals two important features of polymer crystal formation at high-driving forces in entangled polymer melts based on molecular dynamics simulations of polyethylene, a prototypical polymer. First, in contrast to existing literature on small-molecule crystallization, it is demonstrated that the heat released during polymer crystallization does not appreciably influence molecular-level structural details of early-stage, crystalline clusters (i.e., polymer crystal nuclei). Second, it is revealed that early-stage polymer crystallization (i.e., crystal nucleation) can occur without substantial chain-level relaxation and conformational changes, which is consistent with previous experimental work and yet in contrast to many previous computational studies. Given the conditions used to process polyethylene, the separation of timescales associated with crystallization and chain-level processes is anticipated to be of substantial importance to processing strategies. This study thus provides insights that highlight new research directions for understanding polymer crystallization under industrially-relevant conditions while also providing guidance as to how this work can be undertaken.</p>

Confinement Effects in Polymer Crystal Nucleation from the Bulk to Few-Chain Systems

2006 ◽  
Vol 97 (24) ◽  
Author(s):  
Michael V. Massa ◽  
Jessica L. Carvalho ◽  
Kari Dalnoki-Veress
Keyword(s):  
Crystal Nucleation ◽  
Confinement Effects ◽  
Polymer Crystal

Polymer crystal nucleation with confinement-enhanced orientation dominating the formation of nanohybrid shish-kebabs with multiple shish

RSC Advances ◽  
2016 ◽  
Vol 6 (56) ◽  
pp. 50451-50459 ◽  
Author(s):  
Yijing Nie ◽  
Tongfan Hao ◽  
Ya Wei ◽  
Zhiping Zhou
Keyword(s):  
Crystal Nucleation ◽  
Polymer Crystal

An unexpected NHSK structure with multiple shish is observed. The aligned fillers act as multiple shish and the polymer crystal lamellae form kebabs.

Chain-End Modification: A Starting Point for Controlling Polymer Crystal Nucleation

2021 ◽  
Vol 54 (4) ◽  
pp. 1599-1610
Author(s):  
Kyle Wm. Hall ◽  
Simona Percec ◽  
Wataru Shinoda ◽  
Michael L. Klein
Keyword(s):  
Crystal Nucleation ◽  
Polymer Crystal ◽  
Starting Point

A New Defect in Polyethylene Single Crystals

1973 ◽  
Vol 31 ◽  
pp. 70-71
Author(s):  
E. L. Thomas ◽  
S. L. Sass
Keyword(s):  
Single Crystals ◽  
Screw Dislocation ◽  
Small Distance ◽  
Dipole Model ◽  
Dislocation Dipole ◽  
Chain Folding ◽  
Black And White ◽  
Polymer Crystal ◽  
Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

scholarly journals The exploration of the crystal nucleation parameters and physico-chemical analysis of a single crystal: 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine

RSC Advances ◽  
2021 ◽  
Vol 11 (26) ◽  
pp. 15710-15721
Author(s):  
Paavai Era ◽  
RO. MU. Jauhar ◽  
V. Viswanathan ◽  
M. Madhangi ◽  
G. Vinitha ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Single Crystal ◽  
Chemical Properties ◽  
Crystal Nucleation ◽  
Nucleation Parameters ◽  
Physico Chemical

This paper discusses the structural orientations and the physico-chemical properties of a single crystal of 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine (2ADT).

scholarly journals Viscosity solutions for a polymer crystal growth model

2011 ◽  
Vol 60 (3) ◽  
pp. 895-936
Author(s):  
Pierre Cardaliaguet ◽  
Olivier Ley ◽  
Aurelien Monteillet
Keyword(s):  
Crystal Growth ◽  
Growth Model ◽  
Viscosity Solutions ◽  
Polymer Crystal

scholarly journals Factors affecting cholesterol monohydrate crystal nucleation time in model systems of supersaturated bile.

1985 ◽  
Vol 26 (9) ◽  
pp. 1102-1111 ◽  
Author(s):  
A Kibe ◽  
M A Dudley ◽  
Z Halpern ◽  
M P Lynn ◽  
A C Breuer ◽  
...  
Keyword(s):  
Model Systems ◽  
Crystal Nucleation ◽  
Nucleation Time ◽  
Factors Affecting ◽  
Cholesterol Monohydrate
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