Disentangle model differences and fluctuation effects in DPD simulations of diblock copolymers

In the widely used dissipative particle dynamics (DPD) simulations 1, polymers are commonly modeled as discrete Gaussian chains interacting with soft, finite-range repulsions. In the original DPD simulations of microphase separation of diblock copolymer melts by Groot and Madden 2 , the simulation results were compared and found to be consistent with the phase diagram for the "standard model" of continuous Gaussian chains with Dirac δ-function interactions obtained from self-consistent field (SCF) calculations. Since SCF theory is a mean-field theory neglecting system fluctuations/correlations while DPD simulations fully incorporate such effects, the model differences are mixed with the fluctuation/correlation effects in their comparison. Here we report the SCF phase diagram for exactly the same model system as used in DPD simulations. Comparing our phase diagram with that for the standard model highlights the effects of chain discretization and finite-range interactions, while comparing our phase diagram with DPD simulation results unambiguously (without any parameter-fitting) reveal the effects of system fluctuations/correlations neglected in the SCF theory.

Name thesis:degree_name

Master of Science (M.S.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Chemical and Biological Engineering

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

2013

Authors dc:creator

• Sandhu, Paramvir, author
• Wang, Qiang (David), advisor
• Bailey, Travis S., committee member
• Szamel, Grzegorz, committee member

• copolymers
• SCFT
• fluctuations
• DPD
• diblock

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.018819

OAI identifier oai:identifier

oai:mountainscholar.org:10217/79182