Collapse dynamics of a polymer chain: Theory and simulation

• Published in: Europhysics letters 2002-08, Vol.59 (3), p.391-397
• Main Authors: Abrams, C. F, Lee, N.-K, Obukhov, S. P
• Format: Article
• Language: English
• Subjects: 61.25.Hq; 64.60.Ak; 83.10.Rs; Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Solution and gel properties
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/epl/i2002-00207-5

We present a scaling theory describing the collapse of a homopolymer chain in poor solvent. At time t after the beginning of the collapse, the original Gaussian chain of length N is streamlined to form N/g segments of length R(t), each containing $g \sim t$ monomers. These segments are statistical quantities representing cylinders of length $R \sim t^{1/2}$ and diameter but structured out of stretched arrays of spherical globules. This prescription incorporates the capillary instability. We compare the time-dependent structure factor derived for our theory with that obtained from ultra-large-scale molecular-dynamics simulation with explicit solvent. This is the first time such a detailed comparison of theoretical and simulation predictions of collapsing chain structure has been attempted. The favorable agreement between the theoretical and computed structure factors supports the picture of the coarse-graining process during polymer collapse.