What is the size of a ring polymer in a ring-linear blend?

Iyer, Balaji V. S. ; Lele, Ashish K. ; Shanbhag, Sachin (2007) What is the size of a ring polymer in a ring-linear blend? Macromolecules, 40 (16). pp. 5995-6000. ISSN 0024-9297

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Official URL: http://pubs.acs.org/doi/abs/10.1021/ma0709295

Related URL: http://dx.doi.org/10.1021/ma0709295


In melts, ring polymers assume more compact conformations compared to linear chains with the same degree of polymerization Nr, i.e. Rr ~ Nrν with ν ≈ 0.4, where Rr is the radius of gyration. Upon gradually substituting some of the ring polymers with linear chains, the ring molecules swell. In the limit of infinite dilution, their size scales as Rr ~ Nr0.5. We present a scaling argument based on the blob model to capture this transition. Ring-linear blends are modeled as a semidilute solution of ring polymers in a ν-solvent consisting of linear chains. The model predicts that the size of the ring polymer remains unchanged up to the overlap concentration ct. Beyond ct the size of the ring shrinks according to Rr crβ, where β = 2ν - 1 = -1/5 for ν = 0.4. The overlap concentration depends on the degree of polymerization of the ring according to ct~ 1/ √Nτ. These predictions were tested by performing Monte Carlo simulations of ring-linear blends using the bond-fluctuation model. The results of the simulation for Nr = 150 and 300 blended at different concentrations with linear chains of the same degree of polymerization validate the scaling model.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:60570
Deposited On:09 Sep 2011 06:57
Last Modified:09 Sep 2011 06:57

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