82 research outputs found
Density Functional Simulation of Spontaneous Formation of Vesicle in Block Copolymer Solutions
We carry out numerical simulations of vesicle formation based on the density
functional theory for block copolymer solutions. It is shown by solving the
time evolution equations for concentrations that a polymer vesicle is
spontaneously formed from the homogeneous state. The vesicle formation
mechanism obtained by our simulation agree with the results of other
simulations based on the particle models as well as experiments. By changing
parameters such as the volume fraction of polymers or the Flory-Huggins
interaction parameter between the hydrophobic subchains and solvents, we can
obtain the spherical micelles, cylindrical micelles or bilayer structures, too.
We also show that the morphological transition dynamics of the micellar
structures can be reproduced by controlling the Flory-Huggins interaction
parameter.Comment: 29 pages, 11 figures, to appear in J. Chem. Phy
Density Functional Theory for Block Copolymer Melts and Blends
We derive an expression for the free energy of the blends of block copolymers
expressed as a functional of the density distribution of the monomer of each
block. The expression is a generalization of the Flory-Huggins-de Gennes theory
for homo polymer blends, and also a generalization of the Ohta-Kawasaki theory
for the melts of diblock copolymers. The expression can be used for any blends
of homopolymers and block copolymers of any topological structure. The
expression gives a fast and stable computational method to calculate the micro
and macro phase separation of the blends of homopolymers and block copolymers.Comment: 25 pages, 9 figures, will appear in Macromolecule
Single Chain Slip-Spring Model for Fast Rheology Simulations of Entangled Polymers on GPU
We propose a single chain slip-spring model, which is based on the
slip-spring model by Likhtman [A. E. Likhtman, Macromolecules, 38, 6128
(2005)], for fast rheology simulations of entangled polymers on a GPU. We
modify the original slip-spring model slightly for efficient calculations on a
GPU. Our model is designed to satisfy the detailed balance condition, which
enables us to analyze its static or linear response properties easily. We
theoretically analyze several statistical properties of the model, such as the
linear response, which will be useful to analyze simulation data. We show that
our model can reproduce several rheological properties such as the linear
viscoelasticity or the viscosity growth qualitatively. We also show that the
use of a GPU can improve the performance drastically.Comment: 30 pages, 8 figures, 1 table, to appear in Nihon Reoroji Gakkaishi
(J. Soc. Rheol. Jpn.
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