Dissipative Particle Dynamics Approaches to Modeling …
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the B block length lead to a morphology transition from vesicles to bowl-like aggregates. The study also showed that a transition from a bowl-like structure to a vesicle
is caused by increasing the solvophobicity of the B block. Zhou et al. examined the
effect of solvent selectivity, concentration, rod and coil lengths on the morphology
of self-assembled rod-coil-rod block copolymers [131]. The study showed that in the
coil-selective solvent the aggregate morphology transitions from a sphere to other
morphologies. However, in the rod-selective solvent the reverse is observed.
Shape transitions in BCP-based aggregates or during the self-assembly of BCPs is
a phenomenon which can only be resolved over long time scales, and has been examined using DPD simulations. Li et al. examined shape transformations of vesicles
composed of amphiphilic triblock copolymers, and reported vesicles with complex
shapes, such as starfish-shaped, toroidal, long rodlike, and inverted vesicles (Fig. 2c)
[132]. These vesicle shapes had not been reported earlier by computational studies
and were in agreement with theoretical predictions and experimental observations.
The shape transformations were induced by tuning the interaction potential parameters. Li investigated shape transformations of two-component vesicles composed of
diblock copolymers and obtained various axisymmetric (sphere, oblate, pear, dumbbell) and non-axisymmetric (boomerang, multiple-armed starfish) vesicular structures [133]. Phase diagrams showing the dependence of the shapes on the reduced
volume, reduced area-difference and the length of hydrophobic blocks were found
to be consistent with theoretical predictions.
The success of the DPD technique in simulating block copolymers led to its use
to model polymer molecules with increasingly complex architectures to study the
formation of other structures (for example, multicompartment micelles, membranes
and vesicles). Ortiz et al. developed a DPD model of PEO−polyethylethylene
(PEE) diblock copolymer to simulate membrane patches and polymer vesicles [134].
They parameterized the intra- and intermolecular interactions by using experimental
measurements of interfacial tensions and atomistic simulations, respectively and
demonstrated their results to be in good agreement with experiments.
Overall, DPD simulations of neutral BCPs investigated the morphology and
dynamics of the BCPs aggregating in solution on the same scale as experimental
measurements. These studies have provided insight into new morphologies of polymeric structures and a fundamental understanding of the mechanisms underlying
their formation. Hence, the predictions from DPD simulations could be used to
guide future experiments on neutral BCPs.
3.2 Ionic Block Copolymers
DPD allows for much larger systems to be modeled as compared to MD simulations due to significantly reduced interaction complexity, captured via a soft potential. In the past, this reduction in complexity has hindered the use of DPD as a
tool for modeling ionic block copolymers. The difficulty of modeling ionic block
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the B block length lead to a morphology transition from vesicles to bowl-like aggregates. The study also showed that a transition from a bowl-like structure to a vesicle
is caused by increasing the solvophobicity of the B block. Zhou et al. examined the
effect of solvent selectivity, concentration, rod and coil lengths on the morphology
of self-assembled rod-coil-rod block copolymers [131]. The study showed that in the
coil-selective solvent the aggregate morphology transitions from a sphere to other
morphologies. However, in the rod-selective solvent the reverse is observed.
Shape transitions in BCP-based aggregates or during the self-assembly of BCPs is
a phenomenon which can only be resolved over long time scales, and has been examined using DPD simulations. Li et al. examined shape transformations of vesicles
composed of amphiphilic triblock copolymers, and reported vesicles with complex
shapes, such as starfish-shaped, toroidal, long rodlike, and inverted vesicles (Fig. 2c)
[132]. These vesicle shapes had not been reported earlier by computational studies
and were in agreement with theoretical predictions and experimental observations.
The shape transformations were induced by tuning the interaction potential parameters. Li investigated shape transformations of two-component vesicles composed of
diblock copolymers and obtained various axisymmetric (sphere, oblate, pear, dumbbell) and non-axisymmetric (boomerang, multiple-armed starfish) vesicular structures [133]. Phase diagrams showing the dependence of the shapes on the reduced
volume, reduced area-difference and the length of hydrophobic blocks were found
to be consistent with theoretical predictions.
The success of the DPD technique in simulating block copolymers led to its use
to model polymer molecules with increasingly complex architectures to study the
formation of other structures (for example, multicompartment micelles, membranes
and vesicles). Ortiz et al. developed a DPD model of PEO−polyethylethylene
(PEE) diblock copolymer to simulate membrane patches and polymer vesicles [134].
They parameterized the intra- and intermolecular interactions by using experimental
measurements of interfacial tensions and atomistic simulations, respectively and
demonstrated their results to be in good agreement with experiments.
Overall, DPD simulations of neutral BCPs investigated the morphology and
dynamics of the BCPs aggregating in solution on the same scale as experimental
measurements. These studies have provided insight into new morphologies of polymeric structures and a fundamental understanding of the mechanisms underlying
their formation. Hence, the predictions from DPD simulations could be used to
guide future experiments on neutral BCPs.
3.2 Ionic Block Copolymers
DPD allows for much larger systems to be modeled as compared to MD simulations due to significantly reduced interaction complexity, captured via a soft potential. In the past, this reduction in complexity has hindered the use of DPD as a
tool for modeling ionic block copolymers. The difficulty of modeling ionic block