Abstract
We present simulations of a random copolymer model introduced by Kantor and Kardar (Europhys. Lett., 28 (1994) 169). In this model there are two types A, B of monomers. Neighbouring monomers interact with a potential +v0 if they are of the same type, and with −v0 else. When NA ≈ NB, we find a θ-transition at Tθ close to that found by Kantor and Kardar. But this θ-collapse disappears for smaller values of x = |NA - NB| / (NA + NB) than found by these authors, and we argue that it will be indeed difficult to show convincingly that there exists a finite Tθ for any x ≠ 0. The reason for this difficulty is that the polymer first seems to collapse as N = NA + NB increases, but this collapse stops for large N. This suggests that long chains with x ≠ 0 at low temperatures have a structure different from that proposed for copolymers with long-range interactions.