Study on size-dependent optical property of 4,4 ′ -dibromobiphenyl nanocrystals

Xie, Ruimin; Fu, Hongbing; Ji, Xiangling; Chen, Z.H.; Yao, Jiyong

doi:10.1007/s003390100878

Cited by 3 publications

(3 citation statements)

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“…Typically, J-aggregates produce narrower line widths in the spectrum compared to the single chromophore molecules. , The broader line widths observed for both dye species upon incorporation in the PAH/HA films are attributed to a distribution of the aggregation numbers, which has previously been observed to occur in nanocrystal and mixed Langmuir−Blodgett films containing aggregated chromophores. , In this study, it was found that the extent of the red shift is dependent on the concentration of dye in the films with a maximum λ max shift of ∼23 nm for Chromotrope 2R and ∼52 nm for Indoine Blue (Supporting Information). This suggests that wavelength shift is actually due to aggregate formation and not just a result of the dyes being incorporated into the film.…”

Section: Resultssupporting

confidence: 55%

pH-Dependent Loading and Release Behavior of Small Hydrophilic Molecules in Weak Polyelectrolyte Multilayer Films

2004

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The pH-dependent loading and release behavior of small hydrophilic molecular probes in polyallylamine and hyaluronic acid multilayer films was investigated. These studies were carried out using the water-soluble dyes Indoine Blue and Chromotrope 2R, and their loading and release profiles were followed with UV-vis spectroscopy. The results of these studies suggest that the incorporation and release of material from such films depend on the degree of film swelling, the ability of the dye molecules to aggregate in the film, as well as the attractive and repulsive interactions occurring between the probe molecules and the acid-base functional groups in the films. Both the degree of dissociation of the acidbase functional groups and the extent of film swelling are pH-sensitive. As a result, the amount of each dye incorporated in the film also depends on the pH conditions, with a maximum loading capacity of 3.8 × 10 -3 mg/cm 3 of Chromotrope 2R and 5.7 × 10 -2 mg/cm -3 of Indoine Blue. In turn, we found that by manipulating the pH of the release solution it is possible not only to control the rate of the release of the molecular probes but also to regulate the amount of probe material released. In fact, completely trapping the incorporated probes in the multilayer films was also successfully demonstrated. These findings can be rationalized by examining the interactions of the dye molecules with the polyelectrolytes, the ability of molecules to form J-aggregates, and pH-dependent physicochemical properties of the multilayer system, such as the acid-base equilibria of the polyelectrolytes and the swelling behavior of the films. It is believed that this information is fundamentally important to understanding of how to effectively manipulate the films for potential controlled release applications.

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Section: Resultssupporting

confidence: 55%

pH-Dependent Loading and Release Behavior of Small Hydrophilic Molecules in Weak Polyelectrolyte Multilayer Films

2004

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“…With an increase in crystal size of perylene nanoparticles, for example, their excimer emission was weakened, prolonging the decay time . An increase in the size of 4,4‘-dibromobiphenyl nanoparticles made the adsorption band shift in the red direction . The size dependence was found in bathochromic adsorption transition for nanoparticles of a series of pyrazoline derivates .…”

Section: Introductionmentioning

confidence: 87%

“…Organic nanoparticles also show the size dependence in the optical adsorption, , which may result from the aggregate effect, surface effect, or variation of intermolecular interaction . With an increase in crystal size of perylene nanoparticles, for example, their excimer emission was weakened, prolonging the decay time .…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Electrochemical Activity by Small-Sizing the Vinylferrocene-Immobilized Polystyrene Latex Particles

Aoki

2004

Langmuir

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Voltammetry of vinylferrocene (VFc)-immobilized polystyrene(PS)-based latex particles was carried out in aqueous suspensions by changing the size of latex particles in order to investigate the dependence of the electroactivity of the particles on their size. The anodic peak current was controlled by diffusion of the latex. The voltammetric peak currents increased with an increase in the diameter of PS latex particles for a given analytical concentration of the particles, exhibiting the dependence on 1.5 powers of the diameter of the particles. The increase can be explained in terms of combination of the uniform distribution of VFc in the particle, the partial charge transfer, and the Stokes-Einstein equation for diffusion coefficients. The oxidation of VFc occurs in the restricted domain (0.07 µm) from a contact point of the particle with the electrode. The overall reaction mechanism is diffusion of the particle to the electrode, partial oxidation to VFc + , release of VFc + from the particle to the solution, and reduction of the released VFc + .

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Preparation of pyrazoline nanoparticles with a membrane mixer

Jia

Yang

et al. 2006

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Study on size-dependent optical property of 4,4 ′ -dibromobiphenyl nanocrystals

Cited by 3 publications

References 0 publications

pH-Dependent Loading and Release Behavior of Small Hydrophilic Molecules in Weak Polyelectrolyte Multilayer Films

pH-Dependent Loading and Release Behavior of Small Hydrophilic Molecules in Weak Polyelectrolyte Multilayer Films

Enhancement of Electrochemical Activity by Small-Sizing the Vinylferrocene-Immobilized Polystyrene Latex Particles

Preparation of pyrazoline nanoparticles with a membrane mixer

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