Behavior of a random heteropolymer in mixed solvents

Journal Article · Wed Sep 01 04:00:00 EDT 1999 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.479784· OSTI ID:6380466

Chakraborty, A K ^[1]

---

1. Department of Chemical Engineering and Department of Chemistry, University of California, Berkeley, California 94720 (United States)

I use a Landau theory to study the behavior of A[endash]B heteropolymers with disordered sequences immersed in a binary solvent mixture. Segments of type A are preferentially solvated in one type of solvent, and those of type B prefer the other type of solvent. At high temperatures, the behavior is qualitatively the same as that in a single solvent. As the temperature approaches the critical temperature for solvent demixing, however, the chain conformational statistics change dramatically. A phase transition occurs driven by the long-range solvent density fluctuations. The transition is one where on scales larger than a preferred length the chain is collapsed and microphase ordered. On shorter scales it is disordered and exhibits self-avoiding walk statistics. In many circumstances this domain size acquires a limiting value and the system cannot order on shorter length scales by reducing temperature. The ordering disappears when the critical point is approached too closely. Predictions are made for scattering profiles that may be observed in neutron-scattering experiments. [copyright] [ital 1999 American Institute of Physics.]

• OSTI ID: 6380466
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Vol. 111:11; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
BINARY MIXTURES
CHAINS
DENSITY
DISPERSIONS
FLUCTUATIONS
MIXTURES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POLYMERS
SOLUTIONS
SOLVENTS
VARIATIONS