Peptide Amphiphile Monolayer Self-Assembly (2D)

Peptide amphiphiles do not only self-assemble in bulk 3D solution — the same molecules confined to a planar interface (a Langmuir monolayer, or a film adsorbed on a flat substrate) undergo an analogous but genuinely two-dimensional self-assembly process. This simulator models that interfacial system independently: monomers carry a 2D position and a single in-plane orientation angle, and are driven by hydrophobic tail burial (Lennard-Jones attraction), Debye-screened electrostatic repulsion between charged headgroups, and a nematic alignment torque re-derived directly in 2D — where it reduces to the exact, closed-form sin(2Δθ) coupling of classical 2D liquid-crystal theory, rather than the vector-projection routine the 3D bulk version needs. Adjust monomer concentration, ionic strength, temperature and β-sheet propensity, and watch nematic fibrils nucleate, elongate or disperse while the global nematic order, assembled fraction, largest fibril size and local bond order are tracked live.