The concept of edge-edge attractions in nanodisc suspensions of double chain surfactants is introduced which is relevant also to catanionic surfactants and lipids. This gives a natural explanation to a number of features observed like segregation into regions of double chain and single chain surfactants in catanionic nanodiscs, vesicle to micelle transition induced by single chain surfactants, coexistence of micelles, vesicles, sheets, etc., and distribution of critical micelle concentrations. The model proposed gives the expressions for some of the properties which are compared with available experiments. (C) 2011 Elsevier B.V. All rights reserved.