Soluble complexes in aqueous mixtures of low charge density comb polyelectrolyte and oppositely charged surfactant probed by scattering and NMR

Complex coacervate core micelles

“…Comicellization of surfactants with oppositely charged flexible copolymers, typically leads to the formation of core-shell aggregates, with a disordered core consisting of one to several hundred surfactant micelles connected by the polyelectrolyte copolymer blocks, surrounded by a solvent-swollen shell of the neutral copolymer blocks [60,124,125,129]. On the other hand, comicellization with stiff copolymers may lead to the formation of rod-like complexes as was reported for aqueous mixtures of SDS and PMOTAC-g-PEO [69]. The solution behaviour of surfactant-containing C3Ms strongly depends on the molecular characteristics of both the copolymer (N core , N corona ) and the surfactant (single/double/triple tail) [135].…”

“…Ionic-neutral block, graft, and statistical copolymers have been complexed with a wide variety of oppositely charged surfactants, such as AOT, [ [133,139] DDDAB, [135,137] DTAB, [136] DODAB, [135,137] DPC, [136] DTAB, [60,61,105,[124][125][126][127][128][129]174] FSA, [184] FSE, [184] CTAB, [130][131][132]137,167] OA, [70] SD, [185] SDS, [57,68,69,125,126,225,239] SFD, [185] TDS, [68] TOMAB, [135,137] TDTAB, [136] bile salts, [47] and fatty acid salts [46]. Comicellization of surfactants with oppositely charged flexible copolymers, typically leads to the formation of core-shell aggregates, with a disordered core consisting of one to several hundred surfactant micelles connected by the polyelectrolyte copolymer blocks, surrounded by a solvent-swollen shell of the neutral copolymer blocks [60,124,125,…”

“…For CMC ≥ CMC Icr , when the solution ionic strength has exceeded the so-called critical ionic strength, I cr (Table 2), micellization no longer occurs. Cooperativity is typically reported for C3M formation [2,18,25,29,68,69,120,135,138,191].…”

“…For a fixed polymer concentration, the critical aggregation concentration, CAC, ( Table 3) where complexation starts to occur is generally displaced by 2-3 orders of magnitude compared to the CMC of the surfactants in absence of the copolymers [46,47,60,61,68,69,131]. The lowest charge ratio, f + , for which complexes are found, was reported to be dependent on the block length ratio N corona /N core [46,47,239] and surfactant tail length, [46] whereas others find no dependence on N corona /N core [60,63].…”

“…An exceptional case has been reported by Bastardo et al, who investigated C3M formation in aqueous mixtures of SDS and a stiff rodlike comb copolymer. Their NMR and SANS experiments indicate that the microenvironment of SDS molecules within C3Ms is significantly more polar than in SDS micelles in absence of copolymer, as SDS is bound to the PMOTAC-g-PEO copolymer in two different ways, both as single molecules and micelles [69]. Laschewsky et al found a lamellar ordering in the core of C3Ms of PTEA 52 -b-PEOA 66 and a fluorinated surfactant, SFD [185].…”