AbstractRheological, elongational flow, and scanning electron microscopy measurements have been performed on cationic monomers associated with specific counterions. The monomers are formed through the reaction of allyl bromide and a variety of dimethylalkylamine derivatives. The results show that above a specific monomer–counterion concentration, highly elongated structures are formed in solution. These structures are adequately described as polymerizable rod‐like micelles. The physical properties of these fluids are interpreted in terms of a micellar sphere to rod transition which gradually occurs over a specific concentration range (>1g/dL, in general). At higher concentrations, these rod‐like entities are capable of interacting with each other. Therefore, even though the forces holding the structures together are certainly weaker than a chemical bond, polymeric‐like properties are observed in these polymerizable viscoelastic fluids.