Lyotropic liquid crystalline phase behavior of a polymeric amphiphile polymerized via their hydrophilic ends

Abstract

The reaction of the nonionic low molecular mass surfactant 3, 6, 9,12,15,18, 21, 24-octaoxaoctatriacontane-1-ol (CH3(CH2)13(OCH2CHe)sOH , C14E8) with acryloyl chloride yielded the monomeric amphiphile II (CH3(CH2)13(OCH2CH2)802C-(CH:CH2) with the polymerizable group located at the hydrophilic end of the molecule. Using radical polymerization, the polymeric surfactant III is obtained. These three surfactant water systems exhibit lyotropic liquid crystalline phases. The binary phase diagrams are compared with each other. In changing from the monomer-water to the polymer -water system a stabilization of the lyotropic mesophases is observed with amphiphiles which are connected via their hydrophilic ends; it is known for the surfactants to be connected via their hydrophobic ends. The appearance of the inverse mesophases, as expected from the molecular geometry of the polymer, is not observed.

Oligoethyleneoxide spacer groups in polymerizable surfactants

“…6), as observed for oligoetheralkanesulfonates [17]. In fact, the poor hydrophilicity of oligoethyleneoxide endcapped by acrylate has been described before [19]. Additionally, the spacer containing monomers exhibit slightly decreased surface tensions at the CMC.…”

Lyotropic Lamellar Polysiloxanes with Isomeric Amphiphilic Side Chains

“…The compound 4 was revealed in moderate yield after several fractional distillations using a short-path apparatus. A further Williamson reaction between 4 and 1-bromo-9-decene using sodium hydride as base generated the tail-type monomer (5). The polymer P1 was isolated from the reaction of 5 with poly(methyl hydrogen siloxane) using the platinum catalyst Pt(COD)Cl 2 and purified by dialysis.…”

“…Thus the LC phases of polysoaps usually exist in a larger temperature and concentration range, compared to the monomeric analogues. [2][3][4][5][6] Furthermore, the sequence of LC phases is often changed when going from a monomer to the corresponding polymer. Hexagonal (H 1 ) and lamellar (L a ) phases are favored in polysoaps, whereas the cubic phases (I), consisting of bcc-or fcc-packed spherical micelles, are suppressed due to the more severe restrictions on the conformation of the polymer backbone in aggregates with strongly curved interfaces.…”

“…Hexagonal (H 1 ) and lamellar (L a ) phases are favored in polysoaps, whereas the cubic phases (I), consisting of bcc-or fcc-packed spherical micelles, are suppressed due to the more severe restrictions on the conformation of the polymer backbone in aggregates with strongly curved interfaces. [4,5] The amphiphilic side chains can be attached to the polymer backbone in several ways. [1] End-on linking of the hydrophilic head groups or the hydrophobic tails to the main chain yields head-type or tail-type polysoaps, respectively.…”

“…Most head-type systems, for example, exhibit a large miscibility gap extending to low temperatures at low surfactant concentrations. [3,5,7] However, it is often impossible to separate the influence of the type of side-chain Summary: This paper presents the synthesis of two polymeric surfactants, consisting of a polysiloxane backbone with amphiphilic side chains of the nonionic oligo(ethylene oxide) type, and their phase behavior in aqueous solution, investigated by polarizing microscopy and deuterium NMR spectroscopy using D 2 O as a probe. Two different side chains, which are isomeric glycerol derivatives, were synthesized and attached to poly(methyl hydrogen siloxane) by a hydrosilylation reaction, resulting in a tail-type and a midtype polysurfactant.…”