Аннотация:The influence of the aggregation number on the spinodal stability in solutions of polymer chains bearing a small fraction of chemical groups capable of thermoreversible aggregation was studied. The aggregation is treated as effective attraction whose contribution to the free energy is calculated in the explicit form. The free energy is taken as the sum of the aggregation contribution and the Flory–Huggins lattice gas energy. Quantitative differences between the cases with an aggregation number m of 2, 3, or greater than 3 were found. In
particular, owing to high crossover cooperativity at m > 3, spinodal curves can have two local minima each: nonaggregation at \phi = 0 and aggregation at a finite volume fraction of a polymer. Such behavior of the spinodal suggests a possibility of appearing a triple point in the given systems.