Effects of Block Length and Structure of Surfactant on Self-Assembly and Solution Behavior of Block Ionomer Complexes

Abstract

Several new families of materials have been synthesized on the base of complexes of poly(ethylene oxide)-b-poly(sodium methacrylate) (PEO-b-PMA) with single-, double-, and triple-tail surfactants. Cetylpyridinium bromide (CPB), didodecyldimethylammonium bromide (DDDAB), dimethyldioctadecylammonium bromide (DODAB), and trioctylmethylammonium bromide (TMAB) were used as the surfactant components. In contrast to complexes of homopolymer PMA with these surfactants, which precipitated from aqueous solutions, PEO-b-PMA complexes formed stable dispersions with particle size in the range 100−200 nm. The properties of these systems strongly depended on the lengths of the polyion and nonionic blocks of PEO-b-PMA and the structure of the surfactant. In particular, factors governing stability of these complexes in aqueous dispersion include lyophilizing effect of PEO block (increases with increase in PEO chain length), repulsion of PEO chains (increases with decrease in PMA chain length), and packing parameter of the surfactant. Potential applications of these systems include drug delivery.

Double-Hydrophilic Block Copolymers: Synthesis and Application as Novel Surfactants and Crystal Growth Modifiers

“…The first studies reported in the literature were concerned with complexes of the sodium salt of PEO-block-PMAA and cationic single tail surfactants dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, cetyltrimethylammonium bromide, dodecylpyridinium chloride and cetylpyridinium bromide, [127, 142 -144] as well as cationic double and triple tail surfactants didodecyldimethylammonium bromide (DDDAB), dimethyldioctadecylammonium bromide (DODAB) and trioctylmethylammonium bromide (TMAB). [144] With respect to single tail surfactants, spontaneous vesicle formation with low polydispersity was reported and evidenced by TEM, and f-potential measurements indicated the outer vesicle part to be formed of PEO for the stoichiometric complexes. Fluorescent dye entrapment also confirmed vesicle formation.…”

Complexes of oppositely charged polyelectrolytes and surfactants – recent developments in the field of biologically derived polyelectrolytes

“…2c), which will depend on the charge density of the polyelectrolyte. 17 For the case of block copolymers with one polyelectrolyte block and another water-soluble block (double-hydrophilic copolymers) this leads to the dispersion of such densely packed micelles in a kind of super-aggregate 18,19 and may even yield a liquid crystalline type arrangement. 20 This then obviously requires the persistence length of the polyelectrolyte to be less than the radius of the micelles in order to allow for a dense arrangement of the polyelectrolyte around the micelles, which depends strongly on the curvature of the surfactant aggregates.…”

Evidence of overcharging in the complexation between oppositely charged polymers and surfactants

“…The two systems are very similar in terms of molecular weights and structures but they differ by their electrostatic charge. For charged-neutral diblocks and surfactants with opposite charges, we have established the thermodynamical phase diagrams and found broad regions where hierarchical aggregates spontaneously form via electrostatic selfassembly [34][35][36][37][38][39][40] . These aggregates are termed colloidal complexes because they form through complexation and because of their colloidal nature 21,41 .…”