Revisiting the self-aggregation behavior of cetyltrimethylammonium bromide in aqueous sodium salt solution with varied anions

► Anions of several salts were found to interact with the CTA+ ions prior to micelle formation. ► Aggregation number of CTAB micelles at CMC by SANS, TRFQ, SLS and SFQ follow the order NSANSCMC ≈ NTRFQCMC ≈ NSLSCMC > NSFQCMC. ► The [η] at CMC and packing parameter suggested spherical geometry of micelles. ► SANS results at high [CTAB] fitted to prolate ellipsoidal shape of micelles. ► The anion effects on CMC were found to follow a reverse Hofmeister series.