Molecular characteristics of poly(propylene imine) dendrimers as studied with translational diffusion and viscometry

Корнеева, Е. В.; Meijer, E. W.

doi:10.1007/s00396-001-0625-4

Cited by 39 publications

(44 citation statements)

References 45 publications

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“…The results demonstrate clearly the importance of the solvent. This is particularly visible for DAB‐CN, which exhibits larger hydrodynamic radii in chloroform than in acetone 45, 50. CDCl 3 is probably the best solvent for the core, whereas MeOH is the best one for the TEO segments.…”

Section: Resultsmentioning

confidence: 98%

Treatment of dyeing wastewater by activated carbons derived from municipal sewage sludge

Chen¹,

Jiang²,

Li³

et al. 2011

Env Prog and Sustain Energy

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Activated carbons derived from municipal sewage sludge with pyrolusite modification were prepared. The impact of pyrolusite amount on the activated carbons' characteristics was evaluated by methylene blue tests. The results showed that activated carbons modified with certain amount of pyrolusite (ACP) had better performance than the ones without pyrolusite addition. These activated carbons prepared were effective in COD and color removal in treating an industrial dyeing wastewater. The significant increase of mesopores in the adsorbents was identified as the reason. The optimum pH value for dye adsorption was pH = 3.0 and it took a relatively long contact time to reach equilibrium (≥8 h). Temperature had no obvious effect on dye removal in this study. The regeneration efficiency for three ACPs after two adsorption/regeneration cycles was above 70%. © 2011 American Institute of Chemical Engineers Environ Prog, 2011

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Section: Resultsmentioning

confidence: 98%

Treatment of dyeing wastewater by activated carbons derived from municipal sewage sludge

Chen¹,

Jiang²,

Li³

et al. 2011

Env Prog and Sustain Energy

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“…The expectation that V D increases as n R where R > 1 is also supported by experimental techniques such as SAXS, 41,42 SANS, 23 dilute solution viscometry, 23,78 and translational diffusion 22 as well as computer simulations [22][23][24]42,43,45,47,51,79 where the radius (r) of different dendrimer constructs was measured. Therefore, the change in volume of a dendrimer molecule with increasing generation number is expected to scale as n R where R takes a value greater than unity, [22][23][24][25][41][42][43]45,47,51,78,79 contrary to what was found in Figure 6. According to the trend shown in Figure 6, an excited pyrene probes a volume V Py that increases as ∼n 1 , i.e., more slowly than expected if the pyrenes were free to probe the entire dendrimer interior (V D ) that scales as n R with R > 1.…”

Section: Discussionmentioning

confidence: 99%

A Study of the Dynamics of the Branch Ends of a Series of Pyrene-Labeled Dendrimers Based on Pyrene Excimer Formation

et al. 2010

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A series of pyrene-labeled dendrimers were prepared from generation n = 1 to n = 4 where the pyrenes were attached to the end groups of the dendrimers. Pyrene excimer formation was monitored by steady-state and time-resolved fluorescence spectroscopy as a function of generation number and in terms of the I(E)/I(M) ratio and the average rate constant of excimer formation . To account for the unconventional distribution of pyrene labels which were neither randomly distributed throughout the macromolecule nor limited to just two units which are the only two pyrene-labeling schemes that can be dealt with in a straightforward manner, a Model Free (MF) analysis was applied to the global analysis of the fluorescence decays. Within experimental error, the I(E)/I(M) ratios and obtained from, respectively, the steady-state fluorescence spectra and the time-resolved fluorescence decays were found to increase linearly with increasing generation number. This result is inconsistent with the fact that both the I(E)/I(M) ratio and are proportional to the local concentration of pyrene inside the dendrimer ([Py](loc)) which is not expected to increase with generation number if the excited pyrene is assumed to diffuse freely throughout the dendrimer interior. Since the core-dense model predicts that the dendrimer terminal ends can occupy any position throughout the dendrimer interior, these results suggest that excimer formation between the pyrene-labeled ends is enhanced due to the branched nature of the dendrimer.

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“…The more generally accepted method -pulsed field-gradient spin-echo nuclear magnetic resonance (PFGSE-NMR), which seems to give a better value for D e , is not based on redox reaction and thus does not suffer this drawback [15]. Secondly, the D e of PPI was calculated in an aqueous buffer environment as opposed to the organic environment such as acetonitrile and chloroform [16] where most diffusion coefficients of higher values have been calculated. Solute-solvent interaction (solvation) in this aqueous environment may result in a 'drag' of the molecule thereby lowering its D e .…”

Section: Voltammetric Studies Of G1 Ppi In Solutionmentioning

confidence: 99%

Electrochemical impedimetry of electrodeposited poly(propylene imine) dendrimer monolayer

Arotiba¹,

Owino²,

Baker³

et al. 2010

Journal of Electroanalytical Chemistry

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Molecular characteristics of poly(propylene imine) dendrimers as studied with translational diffusion and viscometry

Cited by 39 publications

References 45 publications

Treatment of dyeing wastewater by activated carbons derived from municipal sewage sludge

Treatment of dyeing wastewater by activated carbons derived from municipal sewage sludge

A Study of the Dynamics of the Branch Ends of a Series of Pyrene-Labeled Dendrimers Based on Pyrene Excimer Formation

Electrochemical impedimetry of electrodeposited poly(propylene imine) dendrimer monolayer

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