Interaction of Hydrophobically Modified Polymers and Surfactant Lamellar Phase

Abstract

We investigate the effect of polysoaps on the phase behavior and membrane elastic properties of the lyotropic lamellar (LR) phase of the nonionic surfactant penta(ethylene glycol) dodecyl ether (C12E5). The polysoap is a hydrophobically modified polymer (hm-polymer) with n-alkyl side groups randomly grafted to a polyacrylate (PAA) backbone. The membrane properties are extracted from small-angle neutron scattering data based on a model developed by Nallet et al. and the excess area method developed by Roux et al. The phase behavior, membrane rigidity, compression modulus, and bilayer mean bending modulus are found to be independent of molecular weight, polydispersity, and hydrophobe length of hm-polymers. The rigidity and compression moduli of membranes increase with increasing polymer concentration and hydrophobe substitution level. A minimum hydrophobic interaction strength (combination of hydrophobe length and hydrophobe substitution level) is required to produce single phase polysoap/lamellar surfactant systems. A scaling model is proposed that defines the boundaries between homogeneous and biphasic solutions based on two criteria: (1) the surface coverage of chain segments between hydrophobes (i.e. blobs) must be less than the available membrane area and (2) the interlamellar spacing must be larger than the blob size. This simple model captures the essential features of the phase diagrams.

Phase behavior and preparation of mesoporous silica in aqueous mixtures of fluorinated surfactant and hydrophobic fluorinated polymer

“…4a and 4b. In mixed membranes of hydrophobically modified polymers and nonionic surfactants, it has been found that if the radius of gyration of polymer is comparable to or greater than one half of the interlamellar distance, phase separation into two co-existing lamellar phases generally occurs [40,41].…”

Coexisting lamellar phases in water–oil–surfactant systems induced by the addition of an amphiphilic block copolymer

“…Although not yet reported for other quaternary systems, polymer-induced formations of two coexisting L α phases were also observed in ternary systems, i.e., water-surfactantamphiphilic block copolymer [27][28][29][30]. For example, Yang et al found that the addition of hydrophobically modified polyacrylates to the binary system H 2 O-C 12 E 5 induces the formation of one vesicular and two L α phases [27].…”

“…For example, Yang et al found that the addition of hydrophobically modified polyacrylates to the binary system H 2 O-C 12 E 5 induces the formation of one vesicular and two L α phases [27]. Kunieda and coworkers added the above-mentioned long-chain A-B silicone surfactant Si 25 C 3 E 51.6 to the system H 2 O-C 12 E 5 and found a polymer-containing L α phase in coexistence with a polymerfree lamellar phase, which is denoted L α in [28].…”

Bending elastic properties of a block copolymer-rich lamellar phase doped by a surfactant: a neutron spin-echo study

“…hydrophobically modied polymers like PAA or PEG; 4,[11][12][13][14] amphiphilic poly(ethylene propylene)-poly(ethylene oxide) added to bicontinuous microemulsions; 10,15,16 and a triblock-peptide added to a lamellar phase.…”