Structure and Dynamics of Dilute Two-Dimensional Ring Polymer Solutions

• Published in: Bulletin of the Korean Chemical Society Vol. 33; no. 3; pp. 975 - 979
• Main Authors: Oh, Young-Hoon, Cho, Hyun-Woo, Kim, Jeong-Min, Park, Chang-Hyun, Sung, Bong-June
• Format: Journal Article
• Language: English
• Published: 대한화학회 20.03.2012
• Subjects: 화학
• ISSN: 0253-2964; 1229-5949
• DOI: 10.5012/bkcs.2012.33.3.975

Structure and Dynamics of dilute two-dimensional (2D) ring polymer solutions are investigated by using discontinuous molecular dynamics simulations. A ring polymer and solvent molecules are modeled as a tangent-hard disc chain and hard discs, respectively. Some of solvent molecules are confined inside the 2D ring polymer unlike in 2D linear polymer solutions or three-dimensional polymer solutions. The structure and the dynamics of the 2D ring polymers change significantly with the number (Nin) of such solvent molecules inside the 2D ring polymers. The mean-squared radius of gyration (R2) increases with Nin and scales as R ~ Nν with the scaling exponent ν that depends on Nin. When Nin is large enough, ν ≈ 1, which is consistent with experiments. Meanwhile, for a small Nin ≈ 0.66 and the 2D ring polymers show unexpected structure. The diffusion coefficient (D) and the rotational relaxation time (τrot) are also sensitive to Nin: D decreases and τ increases sharply with Nin. D of 2D ring polymers shows a strong size-dependency, i.e., D ~ ln(L), where L is the simulation cell dimension. But the rotational diffusion and its relaxation time (τrot) are not-size dependent. More interestingly, the scaling behavior of τrot also changes with Nin; for a large Nin τrot ~ N2.46 but for a small Nin τrot ~ N1.43. KCI Citation Count: 2