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Collapse transition in random copolymer solutions

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Field Value
 
Title Collapse transition in random copolymer solutions
 
Creator DASMAHAPATRA, AK
KUMARASWAMY, G
NANAVATI, H
 
Subject monte-carlo simulations
single homopolymer chain
to-coil transition
globule transition
ionomer solutions
light-scattering
phase-transition
molten globule
theta-polymers
model
 
Description We present dynamic Monte Carlo lattice simulations of the coil to globule collapse of single chains of a copolymer comprising monomer units, m and c, wherein there is a net attractive interaction between c-units. As the copolymer is cooled, the solvent quality becomes poorer, and the size of the chain decreases, driven by the net m-m and c-c attractions. The strong c-c attraction increases the overall solvophobicity of the chain relative to a homopolymer and, therefore, copolymers collapse more abruptly and at a higher effective temperature relative to homopolymers. We compare copolymers with homopolymers by rescaling collapse data to the same theta values to account for the effect of overall solvophobicity. This comparison shows that the behavior of copolymers and the corresponding homopolymers is identical as the chain size reduces from high temperatures to the theta value. Beyond theta, copolymers with c-content < similar to 50% collapse more abruptly than either homopolymer, after accounting for the difference in overall solvophobicity. Collapse of copolymers containing higher c-content is dominated entirely by the c-c attractions, and these chains behave qualitatively like homopolymers with a higher effective solvophobicity. Analysis of the chain structure during collapse provides a structural reason for the qualitative change in copolymer collapse at low c-content. When such copolymers are cooled below theta, the c-units rapidly aggregate to form an isotropic, compact core surrounded by an anisotropic solvated shell of m-units. The shell densifies as the copolymer is further cooled, but remains anisotropic for the finite chain sizes investigated.
 
Publisher AMER CHEMICAL SOC
 
Date 2011-07-13T19:54:41Z
2011-12-26T12:48:04Z
2011-12-27T05:43:51Z
2011-07-13T19:54:41Z
2011-12-26T12:48:04Z
2011-12-27T05:43:51Z
2006
 
Type Article
 
Identifier MACROMOLECULES, 39(26), 9621-9629
0024-9297
http://dx.doi.org/10.1021/ma061017q
http://dspace.library.iitb.ac.in/xmlui/handle/10054/3756
http://hdl.handle.net/10054/3756
 
Language en