TY - JOUR
T1 - A General Approach for Estimating Lamella-Thickness Distribution in Polymers with Low-Frequency Raman Spectroscopy
T2 - Application to Lamella Formation in Crystallizing Polyethylene
AU - Samuel, Ashok Zachariah
AU - Hamaguchi, Hiro o.
PY - 2018/7/2
Y1 - 2018/7/2
N2 - A general method for estimating lamella-thickness distribution in semicrystalline polymers has been developed and applied to polyethylene (PE). The longitudinal acoustic mode (LAM) of PE appears at very low frequencies (i.e., (Formula presented.) 8–20 cm−1) in the Raman spectrum. It represents a distribution of lamellae of varying thicknesses. We propose a distribution function that converts a low-frequency LAM Raman band into the corresponding lamellae-thickness distribution. By using this distribution function, we can study lamella formation in crystallizing PE to elucidate the influence of supercooling and determine critical lamella thickness, the minimum chain length at which folding occurs, and the associated thermodynamic parameters accurately. This method has a general applicability toward the examination of polymer crystallization in an accurate and straightforward manner. Understanding the molecular details of polymer crystallization has applications, particularly in polymer thin-film photovoltaics and polymer processing, beyond its fundamental academic significance.
AB - A general method for estimating lamella-thickness distribution in semicrystalline polymers has been developed and applied to polyethylene (PE). The longitudinal acoustic mode (LAM) of PE appears at very low frequencies (i.e., (Formula presented.) 8–20 cm−1) in the Raman spectrum. It represents a distribution of lamellae of varying thicknesses. We propose a distribution function that converts a low-frequency LAM Raman band into the corresponding lamellae-thickness distribution. By using this distribution function, we can study lamella formation in crystallizing PE to elucidate the influence of supercooling and determine critical lamella thickness, the minimum chain length at which folding occurs, and the associated thermodynamic parameters accurately. This method has a general applicability toward the examination of polymer crystallization in an accurate and straightforward manner. Understanding the molecular details of polymer crystallization has applications, particularly in polymer thin-film photovoltaics and polymer processing, beyond its fundamental academic significance.
KW - chain structures
KW - crystal growth
KW - lamella thickness
KW - polymers
KW - Raman spectroscopy
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U2 - 10.1002/chem.201800357
DO - 10.1002/chem.201800357
M3 - Article
C2 - 29691936
AN - SCOPUS:85049318552
VL - 24
SP - 9333
EP - 9339
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 37
ER -