Polymer Conformation: Worm-Like Chain

WLC Parameters

Contour length L: 100 nm Persistence length ℓ_p: 50 nm Temperature kT: 1.0 Ensemble size: 30 Applied force f: 0.0 pN

⟨R²⟩^(1/2):—

⟨R_end⟩:—

x_WLC(f):—

Regime:—

⟨u(s)·u(0)⟩ = e^(-s/ℓ_p)

The WLC model describes semiflexible polymers (DNA, actin, collagen). Tangent-tangent correlations decay with persistence length ℓ_p.

ℓ_p ≫ L: rod-like (stiff)
ℓ_p ≪ L: random coil
ℓ_p ~ L: semiflexible (DNA!)

Marko-Siggia interpolation: fℓ_p/kT = ¼(1-x/L)^(-2) - ¼ + x/L

Worm-Like Chain Polymer

WLC Parameters