COLLAPSE OF TETHERED CHAINS DUE TO N-CLUSTERS, WHEN BINARY INTERACTIONS ARE WEAKLY REPULSIVE, BUT TERNARY INTERACTIONS ARE WEAKLY ATTRACTIVE

The collapse of tethered chains of 100 and 400 bonds has been simulated on a tetrahedral lattice. The density of the unperturbed tethered chains ranges from extremely dilute to weak overlap. When the binary interactions are weakly repulsive, attractive ternary interactions can produce a sharp collapse of the chains. The collapse is initiated from the ''inside'' (= near the grafting/tethering surface). It takes place over a narrow range of the ternary interaction if the chains are monodisperse. Since the value of the ternary interaction required for collapse depends on the number of bonds, the transition may not appear sharp if it is measured with polydisperse chains.