Release Of Active Species Research Articles

Proton affinity and gas-phase basicity of pyrogallol and phloroglucinol: a computational study

We report the proton affinities (PAs) and gas-phase basicities (GBs) of pyrogallol (1,2,3-trihydroxybenzene) and phloroglucinol (1,3,5-trihydroxybenzene), as determined by high level quantum chemical calculations and a series of isodesmic proton transfer reactions. These yet unmeasured values have relevance to release of active species from nanocarriers derived from the calixarene family of macrocycles. The PAs and GBs obtained for these two trihydroxybenzene isomers are compared and contrasted with those obtained previously for the third isomer, hydroxyquinol (1,2,4-trihydroxybenzene). Preferred protonation sites and relative thermochemical values are analyzed in terms of electron delocalization effects and the consequent disruption of intramolecular hydrogen bonding.

Adsorption and Release of Active Species into and from Multifunctional Ionic Microgel Particles

We synthesize monodisperse ionic microgel particles which undergo a large change in volume in response to environmental stimuli such as pH and temperature. In addition, the study elucidates the effective uptake and release of rheology modifiers from these microgel particles to alter the bulk viscosity of a surrounding fluid. Moreover, we found that the prepared ionic microgel particles can demonstrate abilities to adsorb and repel iron oxide nanoparticles (Fe3O4-NPs) upon pH variation. The extent of the loading of Fe3O4-NPs within the colloidal particles and morphology can be manipulated by tunable interactions between the Fe3O4-NPs and ionic microgel particles.

Poly(vinylpyridine) Core/Poly(N-isopropylacrylamide) Shell Microgel Particles: Their Characterization and the Uptake and Release of an Anionic Surfactant

The use of microgel particles for controlled uptake and release of active species has great potential. The compatibility of microgel particles with their environment and the functionality of the particles can be achieved by modification of the core microgel through the addition of a shell. In this work, core-shell microgel particles, with a pH-responsive core (polyvinylpyridine) and a temperature-responsive shell (poly-N-isopropylacrylamide), have been prepared and characterized. The uptake and release of an anionic surfactant from the microgels has been investigated as a function of solution pH and temperature. The results indicate that electrostatic attraction between the anionic surfactant and the cationically charged core of the microgel particles is the dominant mechanism for absorption of the surfactant into the core-shell microgel particles.