Figure 2. Majority-rules reactions.

Possible reactions and corresponding enthalpy differences in the majority-rules model, where (R)-chiral (red) and (S)-chiral (blue) monomers reversibly associate into helical supramolecular copolymers with opposite helicity (P and M type). Possible reactions are the formation of P- or M-type dimers, the dissociation of existing dimmers, and the addition or dissociation of monomeric units to/from existing oligomers/polymers. The addition of chiral monomers to supramolecular polymers having their preferred helicity (that is, R-chiral monomers prefer to associate with P-type helical aggregates while S-chiral monomers prefer to associate with M-type helical aggregates) is described by an elongation enthalpy and entropy ΔS⁰. The addition of chiral monomers to supramolecular polymers with the wrong handedness (that is, association of an R-chiral monomer to an M-type helical supramolecular polymer and association of an S-chiral monomer to a P-type helical supramolecular polymer) is penalized by a mismatch enthalpy . Nucleation of a new homo or heterochiral dimer of any type is penalized by a nucleation penalty and an additional for each monomer of the wrong chirality with respect to the aggregate helicity.