Vesicular structures are promising materials for encapsulation applications, and vesicles composed from block copolymers are attractive in this regard because of their stability and tunability. However, vesicle formation from copolymers generally requires specialized procedures. This article demonstrates that ethylene oxide/butylene oxide diblock copolymers spontaneously form micrometer-sized, multilamellar vesicles ("onions") over a broad range of concentrations upon simple mixing with water. These structures likely form due to the relatively large volume-to-length ratio of the butylene oxide hydrophobe, and vesicle formation also depends on the length of the ethylene oxide headgroup. Structures were characterized using plane-polarized light microscopy, dynamic light scattering, and cryogenic scanning electron microscopy. The multilamellar vesicles survive sonication and moderate shear. Vesicle size can be reduced by extrusion through a porous membrane, but final diameter is independent of shear rate and membrane pore size.

We introduce a controlled ionic coacervation (CIC) process that rapidly forms uniform, gel-like latex films with significant mechanical integrity without loss of water from the film. This process uses latex particles that contain both strong cationic charges and weak protonated acid groups. An increase in pH ionizes the weak acid and triggers the rapid setting of the latex films. The necessary increase in pH can be achieved by coating the latex onto an alkaline surface (such as concrete) or by controlled release of a fugitive acid (such as carbon dioxide). We explore the effect of latex composition and concentration on this process. We show that the CIC process does not require a water-soluble polymer to obtain the rapid-set film properties. Our proposed mechanism for CIC process is consistent with models for rapid, irreversible, particle-particle aggregation.

Morphologically complex amorphous calcium phosphate nanostructures are synthesized within supersaturated water-in-oil miniemulsions stabilized by a mixture of a calcium bis­(2-ethylhexyl)­phosphate (Ca­(DEHP)2) surfactant and poly­(ethylene oxide)19-poly­(propylene oxide)69-poly­(ethylene oxide)19 (P123) triblock copolymer. Solvent evaporation at room temperature results in self-supporting viscous organogels comprising an interconnected network of calcium phosphate nanofilaments embedded within a continuous polymer/surfactant matrix. The P123/DEHP/calcium phosphate organogels are employed as a bioactive filler for the occlusion of exposed dentine tubules using a standard bovine tooth model.

Polyampholyte latexes can exist within a certain pH range as low-viscosity aqueous dispersions, while upon a pH shift to the vicinity of the isoelectric point they undergo ionic coacervation. Three classes of coacervation latexes were synthesized and evaluated for their suitability for use in tablet coating applications. Pharmaceutical tablet coatings are commonly based on hydroxypropyl methyl cellulose, poly(vinyl alcohol), and acrylic polymers. Because of the high viscosity of their aqueous solutions, and to the consequent required low concentrations of the tablet coating polymers in the coating solutions to enable sufficiently low viscosity for effective spray application, the current commercial pharmaceutical tablet coating technology requires the removal of large amounts of water during the manufacturing process. In this work, films prepared from high-solids, low-viscosity coacervated acrylic latexes showed good hardness, very low tackiness, an excellent combination of optical properties, and very low water vapor permeability. V C 2013 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2014, 131, 40049. Polyampholytes have found application in areas such as lithographic film, 19 drag reduction, 20 membranes, 21 water-based coatings, 22 papermaking, 23 skin care, 24 and controlled drug release. 25 In addition, polyampholyte latexes have been developed for various types of fast-setting industrial coatings (on cement, metal, glass, wood, and other surfaces). 10,26 Additional Supporting Information may be found in the online version of this article.