polysim

Polymer structure generator and physical property simulator written in Rust.

Given a BigSMILES string, polysim generates concrete polymer chains (as SMILES) and computes physical/chemical properties such as glass transition temperature, molecular weight, and more.

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Features

Status	Feature
✅	Linear homopolymer generation
🔜	Random / alternating / block copolymers
🔜	Branched polymers, graft copolymers, macromonomers
✅	Chain length by repeat count
✅	Chain length by target Mn (ByTargetMn)
✅	Chain length by monoisotopic mass (ByExactMass)
✅	Average molecular weight (IUPAC standard atomic weights)
✅	Monoisotopic mass (most abundant isotope per element)
✅	Tg estimation — Fox equation
🔜	Tg estimation — Van Krevelen group contributions
🔜	Crystallisation tendency
🔜	Hildebrand solubility parameter
🔜	Melting temperature Tm

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Quick start

# Cargo.toml
[dependencies]
polysim-core = "0.1"

Build a chain and read its molecular weight

use polysim_core::{parse, builder::{linear::LinearBuilder, BuildStrategy}};

// Polyéthylène — 100 unités répétées
let bs = parse("{[]CC[]}").unwrap();
let chain = LinearBuilder::new(bs, BuildStrategy::ByRepeatCount(100))
    .homopolymer()
    .unwrap();

println!("Repeat units : {}", chain.repeat_count); // 100
println!("Mn           : {:.1} g/mol", chain.mn);  // 1410.7 g/mol
println!("SMILES       : {}…", &chain.smiles[..20]);

Target a specific Mn

use polysim_core::{parse, builder::{linear::LinearBuilder, BuildStrategy}};

// Polypropylène — viser Mn ≈ 10 000 g/mol
let bs = parse("{[]CC(C)[]}").unwrap();
let chain = LinearBuilder::new(bs, BuildStrategy::ByTargetMn(10_000.0))
    .homopolymer()
    .unwrap();

println!("Repeat units : {}", chain.repeat_count); // ≈ 237
println!("Mn réel      : {:.1} g/mol", chain.mn);  // ≈ 9 996 g/mol

Compute masses independently

use polysim_core::{parse, builder::{linear::LinearBuilder, BuildStrategy},
                   properties::molecular_weight::{average_mass, monoisotopic_mass}};

let bs = parse("{[]CC(c1ccccc1)[]}").unwrap(); // polystyrène
let chain = LinearBuilder::new(bs, BuildStrategy::ByRepeatCount(10))
    .homopolymer()
    .unwrap();

println!("Masse moyenne       : {:.2} g/mol", average_mass(&chain));
println!("Masse monoisotopique: {:.2} g/mol", monoisotopic_mass(&chain));

Glass transition temperature

use polysim_core::properties::thermal::tg_fox;

// Tg d'un mélange 70/30 PS/PMMA  (PS : 373 K, PMMA : 378 K)
let tg = tg_fox(&[(0.70, 373.0), (0.30, 378.0)]);
println!("Tg ≈ {tg:.1} K");

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Build strategies

pub enum BuildStrategy {
    /// Nombre exact d'unités répétées.
    ByRepeatCount(usize),

    /// Mn cible (masse moléculaire moyenne, g/mol).
    /// Le nombre de répétitions est déduit par extrapolation linéaire.
    ByTargetMn(f64),

    /// Masse monoisotopique cible (g/mol).
    /// Même logique que ByTargetMn mais avec les masses monoisotopiques.
    ByExactMass(f64),
}

Après construction, chain.mn contient toujours la masse moléculaire moyenne calculée, quelle que soit la stratégie utilisée.

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Polymer architectures

Architecture	Builder	Statut
Homopolymer	LinearBuilder::homopolymer	✅
Random copolymer	LinearBuilder::random_copolymer	🔜
Alternating copolymer	LinearBuilder::alternating_copolymer	🔜
Block copolymer	LinearBuilder::block_copolymer	🔜
Comb / branched	BranchedBuilder::comb_polymer	🔜
Graft copolymer	BranchedBuilder::graft_copolymer	🔜
Macromonomer	BranchedBuilder::macromonomer	🔜

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Workspace layout

polysim/
├── crates/
│   ├── polysim-core/     # library (published to crates.io)
│   │   └── src/
│   │       ├── builder/      # chain generators
│   │       ├── polymer/      # PolymerChain type
│   │       └── properties/   # Tg, MW, …
│   └── polysim-cli/      # command-line tool (not yet published)

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Development

Prerequisites

• Rust stable (≥ 1.70)
• make (optional, for convenience targets)

Setup

git clone https://github.com/Peariforme/polysim
cd polysim

# Install git hooks (pre-commit: fmt+clippy, pre-push: tests)
git config core.hooksPath .githooks
# or: make install-hooks

Common commands

cargo test --all-features   # run tests
cargo fmt --all             # format code
cargo clippy --all-targets --all-features -- -D warnings  # lint
cargo bench                 # run benchmarks
cargo doc --open            # browse documentation

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References

• Lin, T.-S. et al. (2019). BigSMILES: A Structurally-Based Line Notation for Describing Macromolecules. ACS Central Science 5, 1523–1531. doi:10.1021/acscentsci.9b00476
• Fox, T. G. (1956). Influence of diluent and of copolymer composition on the glass temperature of a polymer system. Bull. Am. Phys. Soc. 1, 123.
• Van Krevelen, D. W. & te Nijenhuis, K. (2009). Properties of Polymers, 4th ed. Elsevier.

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License

MIT — see LICENSE.