Struct PolymerChain 

pub struct PolymerChain {
    pub n_segments: u32,
    pub segment_length: f64,
    pub persistence_length: f64,
    pub temperature: f64,
}

Freely jointed chain (FJC) model for polymer elasticity.

Provides the Langevin-based force-extension relation and Flory-Huggins mixing free energy.

Fields

n_segments: u32

Number of statistical segments N.

segment_length: f64

Kuhn segment length b (m).

persistence_length: f64

Persistence length l_p (m).

temperature: f64

Temperature (K).

Implementations

impl PolymerChain

pub fn new( n_segments: u32, segment_length: f64, persistence_length: f64, temperature: f64, ) -> Self

Creates a new polymer chain model.

pub fn contour_length(&self) -> f64

Contour length L0 = N * b.

pub fn rms_end_to_end(&self) -> f64

Root-mean-square end-to-end distance R_rms = b * sqrt(N).

pub fn entropic_force(&self, extension: f64) -> f64

Langevin entropic force-extension relation F(r) ≈ (kT/b) * L^{-1}(r/L0).

Uses Pade approximation for inverse Langevin: L^{-1}(x) ≈ x(3-x^2)/(1-x^2).

pub fn flory_huggins_free_energy(&self, phi: f64, chi: f64) -> f64

Flory-Huggins free energy of mixing per lattice site.

ΔF_mix = kT * [φ/N * ln(φ) + (1-φ) * ln(1-φ) + χ * φ * (1-φ)].

Trait Implementations

impl Clone for PolymerChain

fn clone(&self) -> PolymerChain

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PolymerChain

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.