New Nonionic Head Type Polysoaps:  A Way to Reversed Liquid Crystalline Phases

Abstract

The preparation and characterization of new oligooxyethylene alkyl ether surfactants and their corresponding polysoaps are described. The monomers are epoxy-terminated at their hydrophilic end, which allows an AcAc/H2O/AlEt3 catalyzed polymerization to high molecular weight polymers with a water-soluble backbone. The behavior of the monomers and polymers in water and organic solvents is characterized by static and dynamic light scattering. The binary phase diagrams of these surfactants with water display broad lyotropic liquid crystalline phases. The identical chemical constitution of the polymeric backbone and the hydrophilic head groups of the surfactant units enables the formation of reversed aggregates. As a consequence, for the first time, a reversed hexagonal phase in side-chain polymeric surfactants is observed.

Reversible metal-directed assembly of clusters of vesicles

“…A vesicle stock solution at a L a -lecithin concentration of 10 mg cm -3 (1.8 3 10 22 M) was prepared; † the average vesicle mass was 3 3 10 7 g mol -1 corresponding to 54 000 molecules per vesicle and they have a mean hydrodynamic radius R h of 54 nm and radius of gyration R G of 51 nm as determined by dynamic and static light scattering. 6 ‡ This gives r = R G /R h = 0.944 which is close to the theoretical value of r = 1.0 for hollow spheres. 7 The terpy-functionalised phospholipid 2 was prepared as previously described 5 and a 3 wt% amount added to the stock solution of the lecithin to give a total concentration of 2 of 3.29 3 10 24 M. The experimentally measured R h and R G were unchanged by the addition of the functionalised compound 2, indicating no fundamental changes in the solution behaviour of 1 at this level of doping with 2.…”

Association between friction and wear in diarthrodial joints lacking lubricin

“…Lubricin's binding to hydrophobic surfaces such as latex and HOPG, and its localization to aliphatic–aqueous interfaces ( 7 ), are typical of amphipathic polymers. Polysoaps, an amphipathic polymer network, have been shown to possess special properties, including liquid crystalline phases at high concentrations and dense packing of amphiphiles along a polymer backbone, which leads to restricted freedom of conformation and enables steric repulsion ( 32 ). Properties of polysoap aggregates have been observed in SF: under conditions of pressure between cartilage and glass, SF adopts a liquid crystalline structure ( 33 ).…”

Surface active properties of chitosan and its derivatives

“…The most common examples of these substances are that built up of long chain alkyl or alkyl aryl hydrophobic moiety connected with hydrophilic, mostly, polyethylene oxide. Nonionic polymeric surfactants find wide applications in emulsion polymerization; [7] liquid crystalline phases [8], miceller enhanced ultrafiltration [9], surface modifications, [10] destabilization of water in crude oil emulsions [11,12] and other industrial applications.…”