AMBER Archive (2008)

Subject: Re: AMBER: diblock copolymer

From: Jed W Pitera (pitera_at_us.ibm.com)
Date: Tue Jan 22 2008 - 19:01:03 CST

To my knowledge, nobody has tried to use AMBER to simulate diblock
copolymers. The AMBER force fields are relatively detailed all-atom
forcefields that have primarily been parameterized for biomolecules
(proteins, nucleic acids, small molecule ligands) in water solution. There
are no pre-existing parameter sets for typical monomers (polystyrene,
polyethyleneoxide, pMMA, polyisoprene, etc.) seen in diblock copolymers
although you could certainly generate them using ANTECHAMBER if you'd like.

If you are interested in phase behavior and morphology, it will be
difficult to access the necessary length (100 nm+) and time/energy scales
using any all-atom forcefield, especially with molecular dynamics sampling.
Most people working in this area use some sort of coarse-grained
representation (e.g. bead-spring chain with LJ/WCA interactions) and often
use Monte Carlo rather than MD. The only rationale I can see for
simulating one of these systems in an atomistic model is if you're
interested in the detailed interaction of some small molecule (solvent, a
drug molecule, etc.) with the polymer.

I would suggest that you take a look at recent references from places like
the de Pablo and Glotzer groups if you want some examples; there is also a
good review entitled "Monte Carlo simulation of block copolymers" by Binder
and Mueller (Curr. Opin. Coll. & Interf. Sci 2000) that will help.

--Jed

PS: I am happy to answer further questions in this area, but they probably
don't belong on the AMBER reflector.

                                                                           
             "Z Insepov"
             <insepov_at_gmail.co
             m> To
             Sent by: amber_at_scripps.edu
             owner-amber_at_scrip cc
             ps.edu
                                                                   Subject
                                       AMBER: diblock copolymer
             01/17/2008 07:27
             AM
                                                                           
                                                                           
             Please respond to
             amber_at_scripps.edu
                                                                           
                                                                           

Is there any simulation done on diblock copolymers by using AMBER force
field?

Z. Insepov

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