Surface analysis monitoring of polyelectrolyte deposition on Ba0.5Sr0.5TiO3 thin films

Morales-Cruz, Ángel L.; Fachini, E.; Miranda, Félix A.; Cabrera, Carlos R.

doi:10.1016/j.apsusc.2007.04.071

Cited by 7 publications

(6 citation statements)

References 27 publications

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“…Morales-Cruz et al have observed a similar N1s peak position at lower binding energy when protonated primary amines interact with sulfonates in polyelectrolyte multilayers and attribute this to possible H-bond. 43 The two peaks in the N1s envelope for the PEM assembled from 0.5 M buffer exhibit a similar trend, however, the relative change in peak area ratios is much less pronounced. This again confirms that PEM assembly from 0.2 M buffer is much more sensitive to pH than PEM assembly from 0.5 M buffer.…”

Section: Pem Assembly and In Situ Ft-sprmentioning

confidence: 83%

“…The peak at 399.6 contains contributions from three different species: deprotonated amine, amide, and protonated amine interacting with sulfonate, possibly through hydrogen bonds. 43,44 For the PEM assembled from 0.2 M buffer, the fraction of nitrogens in the protonated amine increases with increasing pH. This cannot be explained through consideration of the pH alone.…”

Section: Pem Assembly and In Situ Ft-sprmentioning

confidence: 99%

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Polyelectrolyte Multilayer Assembly as a Function of pH and Ionic Strength Using the Polysaccharides Chitosan and Heparin

2008

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The goal of this work is to explore the effects of solution ionic strength and pH on polyelectrolyte multilayer (PEM) assembly, using biologically derived polysaccharides as the polyelectrolytes. We used the layer-by-layer (LBL) technique to assemble PEM of the polysaccharides heparin (a strong polyanion) and chitosan (a weak polycation) and characterized the sensitivity of the PEM composition and layer thickness to changes in processing parameters. Fourier-transform surface plasmon resonance (FT-SPR) and spectroscopic ellipsometry provided in situ and ex situ measurements of the PEM thickness, respectively. Vibrational spectroscopy and X-ray photoelectron spectroscopy (XPS) provided details of the chemistry (i.e., composition, electrostatic interactions) of the PEM. We found that when PEM were assembled from 0.2 M buffer, the PEM thickness could be increased from less than 2 nm per bilayer to greater than 4 nm per bilayer by changing the solution pH; higher and lower ionic strength buffer solutions resulted in narrower ranges of accessible thickness. Molar composition of the PEM was not very sensitive to solution pH or ionic strength, but pH did affect the interactions between the sulfonates in heparin and amines in chitosan when PEM were assembled from 0.2 M buffer. Changes in the PEM thickness with pH and ionic strength can be interpreted through descriptions of the charge density and conformation of the polyelectrolyte chains in solution.

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Section: Pem Assembly and In Situ Ft-sprmentioning

confidence: 83%

Section: Pem Assembly and In Situ Ft-sprmentioning

confidence: 99%

Polyelectrolyte Multilayer Assembly as a Function of pH and Ionic Strength Using the Polysaccharides Chitosan and Heparin

2008

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“…[26] The band at 1575 cm À1 indicates the presence of primary amines, which are provided by APS. In the case of the polyelectrolyte route (cND-PAH particles), [27] the adsorption of PAH is supported by the presence of the 1571 and 1497 cm À1 bands, which correspond to the amides I and II, respectively. The IR spectrum after the introduction of the maleimide moiety [28,29] showed an intense peak at 1700 cm…”

Section: Resultsmentioning

confidence: 99%

Peptide‐Grafted Nanodiamonds: Preparation, Cytotoxicity and Uptake in Cells

et al. 2008

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Nanodiamonds that were prepared by high pressure/high temperature were functionalized with biomolecules for biological applications. Nanodiamonds (NDs, < or =35 nm) that were coated by silanization or with polyelectrolyte layers were grafted with a fluorescent thiolated peptide via a maleimido function; this led to an aqueous colloidal suspension that was stable for months. These substituted NDs were not cytotoxic for CHO cells. Their capacity to enter mammalian cells, and their localisation inside were ascertained after labelling the nucleus and actin, by examining the cells by confocal, reflected light and fluorescence microscopy.

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“…Other studies exist involving conducting polymer films using the static (contact) and dynamic modes (noncontact and tapping) [8,50,[57][58][59][60][61][62][63][64][65][66][67][68].…”

Section: Vibrating Modesmentioning

confidence: 99%