An Efficient, Regioselective Pathway to Cationic and Zwitterionic N-Heterocyclic Cellulose Ionomers.

Cationic derivatives of cellulose and other polysaccharides are attractive targets for biomedical applications due to their propensity for electrostatically binding with anionic biomolecules, such as nucleic acids and certain proteins. To date, however, relatively few practical synthetic methods have been described for their preparation. Herein, we report a useful and efficient strategy for cationic cellulose ester salt preparation by the reaction of 6-bromo-6-deoxycellulose acetate with pyridine or 1-methylimidazole.

Staudinger Reactions for Selective Functionalization of Polysaccharides: A Review.

Staudinger reactions are frequently highly chemoselective and can occur under very mild conditions, so are attractive methods for efficient functionalization of polysaccharides. This review describes recent investigations that exploit Staudinger-related reactions to effectively alter physical and chemical properties of polysaccharides in order to make them more diversely applicable. Staudinger-related reactions, such as Staudinger reduction, Staudinger ligation, and traceless Staudinger ligation comprise a powerful family of techniques enabling preparation of a wide range of polysaccharide derivatives with excellent chemoselectivity and the potential for excellent regioselectivity when combined with other methods.

Heterobifunctional poly(ethylene oxide) oligomers containing carboxylic acids.

Syntheses of vinylsilyl alcohols having one to three vinyl moieties and their use as initiators for ethylene oxide polymerizations are discussed. Poly(ethylene oxide) oligomers with vinylsilanes at one end and a hydroxyl group at the other were prepared in base-catalyzed reactions. Molecular weights determined from 1H NMR and gel permeation chromatography were close to the targeted values.

Aqueous dispersions of magnetite nanoparticles complexed with copolyether dispersants: experiments and theory.

Magnetite (Fe3O4) nanoparticles have been synthesized and complexed with carboxylate-functional block copolymers, and then aqueous dispersions of the complexes were investigated as functions of their chemical and morphological structures. The block copolymer dispersants had either poly(ethylene oxide), poly(ethylene oxide-co-propylene oxide), or poly(ethylene oxide-b-propylene oxide) outer blocks, and all of them had a polyurethane center block that contained pendent carboxylate groups. The complexes were formed through interactions of the carboxylates with the surfaces of the magnetite nanoparticles.

Blends of amphiphilic trisilanolisobutyl-POSS and phosphine oxide substituted poly(dimethylsiloxane) at the air/water interface.

Mixtures of a polyhedral oligomeric silsesquioxane, trisilanolisobutyl-POSS, and a polar silicone, poly(dimethyl-co-methylvinyl-co-methyl, 2-diphenyl phosphine oxide ethyl) siloxane (PDMS-PO), spread as Langmuir monolayers at the air/water interface are used to examine the surface phase behavior and aggregation of trisilanolisobutyl-POSS as a function of silicone composition. Analyses of the surface pressure-area per monomer (Pi-A) isotherms in terms of the collapse pressures and excess Gibbs free energies of mixing indicate the monolayers form slightly negative deviation mixtures. Direct observations of surface morphology with Brewster angle microscopy in the collapsed regime reveal that the governing factor for aggregation is the collapse Pi of the component with a stronger affinity for water.