TY - JOUR
T1 - Molecular dynamics simulation for morphological change of water-in-oil microemulsion droplets induced by addition of polymer chains
AU - Kurokawa, Takahisa
AU - Urakami, Naohito
AU - Yaegashi, Kaori Nakaya
AU - Sakashita, Ai
AU - Imai, Masayuki
AU - Yamamoto, Takashi
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2011/8/21
Y1 - 2011/8/21
N2 - We carried out molecular dynamics simulations to investigate the morphological change of water-in-oil microemulsion (ME) droplets by addition of polymer chains. Several experiments have shown an increase in the polydispersity of ME droplet size and the morphological transition of spherical ME droplets to a rod-like shape by encapsulating the polymer chain in ME droplets. In order to understand these changes in the ME droplets, we studied the effects of the chain concentration and the interaction strength between chains and surfactant. When the interaction strength was weak, we obtained spherical droplets rather than rod-like droplets. Two types of spherical ME droplets were observed: large spherical droplets containing polymer chains and small spherical droplets without chains, which resulted in a large size polydispersity. However, when the interaction strength was great, a coalescence of ME droplets containing polymer chains was observed and the morphology of the droplets finally changed to a rod-like shape with an increase in the chain concentration. The morphological change can be explained by the competition between the chain-surfactant interaction energy and the surfactant monolayer bending energy, thus the interaction energy prefers a rod-like shape to gain a large contact area between the chains and the surfactant monolayer.
AB - We carried out molecular dynamics simulations to investigate the morphological change of water-in-oil microemulsion (ME) droplets by addition of polymer chains. Several experiments have shown an increase in the polydispersity of ME droplet size and the morphological transition of spherical ME droplets to a rod-like shape by encapsulating the polymer chain in ME droplets. In order to understand these changes in the ME droplets, we studied the effects of the chain concentration and the interaction strength between chains and surfactant. When the interaction strength was weak, we obtained spherical droplets rather than rod-like droplets. Two types of spherical ME droplets were observed: large spherical droplets containing polymer chains and small spherical droplets without chains, which resulted in a large size polydispersity. However, when the interaction strength was great, a coalescence of ME droplets containing polymer chains was observed and the morphology of the droplets finally changed to a rod-like shape with an increase in the chain concentration. The morphological change can be explained by the competition between the chain-surfactant interaction energy and the surfactant monolayer bending energy, thus the interaction energy prefers a rod-like shape to gain a large contact area between the chains and the surfactant monolayer.
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U2 - 10.1039/c1sm05447c
DO - 10.1039/c1sm05447c
M3 - Article
AN - SCOPUS:79961164243
VL - 7
SP - 7504
EP - 7510
JO - Soft Matter
JF - Soft Matter
SN - 1744-683X
IS - 16
ER -