We describe a simple and efficient method for the synthesis of disymmetric bolaforms bearing at least one sulfobetaine head. In this process, we could introduce successively on α, ω-bis(dialkylamino) alkane a sulfobetaine head and a cationic, a sulfobetaine, or a carboxybetaine head, in excellent yield. This is the first synthesis of disymmetric sulfobetaine bolaforms. The method is easily generalized to various types of head functional groups. The wide range of bolaforms produced by this method has been exploited to study their surface properties and to determine the respective roles of the polar heads and the lengths of the spacers (n) on self-aggregation in aqueous media. A critical micellar concentration (cmc) was observed with the compounds with a spacer of 12 carbon atoms (n = 12). Micellization appeared to be consistent with a "wicket-like" conformation, which did not appear to form with the n = 8 compounds.Key words: disymmetric bolaform, sulfobetaine, carboxybetaine, cationic amphiphile, synthesis, surface properties.
We describe here a convenient route to a new family of bolaforms bearing sulfobetaine and cationic heads, which could be scaled up for industrial applications. Their aggregation modes were studied by measurement of surface tension and by dynamic light scattering and transmission electronic microscopy methods. Grafting a hydrophobic chain onto the cationic head modifies both the surface properties and aggregation. Compared to conventional bolaforms, the relationship between the length of the spacer and the side-chain and the resultant hydrophobic interactions are at the origin of these novel properties. Various models of these molecular associations were proposed.Key words: dissymmetric bolaform, sulfobetaine, cationic amphiphile, aggregation.