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Title: Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers

Abstract

Liquid crystalline polymers exhibit a particular richness of behaviors that stems from their rigidity and their macromolecular nature. On the one hand, the orientational interaction between liquid-crystalline motifs promotes their alignment, thereby leading to the emergence of nematic phases. On the other hand, the large number of configurations associated with polymer chains favors formation of isotropic phases, with chain stiffness becoming the factor that tips the balance. In this work, a soft coarse-grained model is introduced to explore the interplay of chain stiffness, molecular weight and orientational coupling, and their role on the isotropic-nematic transition in homopolymer melts. We also study the structure of polymer mixtures composed of stiff and flexible polymeric molecules. We consider the effects of blend composition, persistence length, molecular weight and orientational coupling strength on the melt structure at the nano-and mesoscopic levels. Conditions are found where the systems separate into two phases, one isotropic and the other nematic. We confirm the existence of non-equilibrium states that exhibit sought-after percolating nematic domains, which are of interest for applications in organic photovoltaic and electronic devices.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; National Institute of Standards and Technology (NIST) - Center for Hierarchical Materials Design (CHiMaD); Consejo Nacional de Ciencia y Tecnologia (CONACYT)
OSTI Identifier:
1367200
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Polymers
Additional Journal Information:
Journal Volume: 9; Journal Issue: 3; Journal ID: ISSN 2073-4360
Publisher:
MDPI
Country of Publication:
United States
Language:
English

Citation Formats

Ramírez-Hernández, Abelardo, Hur, Su-Mi, Armas-Pérez, Julio, Cruz, Monica, and de Pablo, Juan. Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers. United States: N. p., 2017. Web. doi:10.3390/polym9030088.
Ramírez-Hernández, Abelardo, Hur, Su-Mi, Armas-Pérez, Julio, Cruz, Monica, & de Pablo, Juan. Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers. United States. doi:10.3390/polym9030088.
Ramírez-Hernández, Abelardo, Hur, Su-Mi, Armas-Pérez, Julio, Cruz, Monica, and de Pablo, Juan. Wed . "Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers". United States. doi:10.3390/polym9030088.
@article{osti_1367200,
title = {Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers},
author = {Ramírez-Hernández, Abelardo and Hur, Su-Mi and Armas-Pérez, Julio and Cruz, Monica and de Pablo, Juan},
abstractNote = {Liquid crystalline polymers exhibit a particular richness of behaviors that stems from their rigidity and their macromolecular nature. On the one hand, the orientational interaction between liquid-crystalline motifs promotes their alignment, thereby leading to the emergence of nematic phases. On the other hand, the large number of configurations associated with polymer chains favors formation of isotropic phases, with chain stiffness becoming the factor that tips the balance. In this work, a soft coarse-grained model is introduced to explore the interplay of chain stiffness, molecular weight and orientational coupling, and their role on the isotropic-nematic transition in homopolymer melts. We also study the structure of polymer mixtures composed of stiff and flexible polymeric molecules. We consider the effects of blend composition, persistence length, molecular weight and orientational coupling strength on the melt structure at the nano-and mesoscopic levels. Conditions are found where the systems separate into two phases, one isotropic and the other nematic. We confirm the existence of non-equilibrium states that exhibit sought-after percolating nematic domains, which are of interest for applications in organic photovoltaic and electronic devices.},
doi = {10.3390/polym9030088},
journal = {Polymers},
issn = {2073-4360},
number = 3,
volume = 9,
place = {United States},
year = {2017},
month = {3}
}

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