Adsorption kinetics and charge inversion in layer-by-layer films from nickel tetrasulfonated phthalocyanine and poly(allylamine hydrochloride)

Silva, Josmary R.; Souza, Nara C. de; Oliveira, Osvaldo N.

doi:10.1016/j.jnoncrysol.2009.12.021

Cited by 8 publications

(7 citation statements)

References 45 publications

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“…The absorbance at 617 nm increased linearly with the number of bilayers, which indicates that the same amount of material was adsorbed for each bilayer deposition. Similar results were reported by Alencar et al and Silva et al [13,21]. However, Au@PAH/ NiTsPc film (from 1 to 7 bilayers) presented two linear regions for film growth, as can be observed in the inset of Figure 2(b): one ranging from 1 to 3 bilayers and the other from 3 to 7 bilayers, as displayed.…”

Section: Lbl Filmssupporting

confidence: 89%

Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

Mercante

Scagion

Pavinatto

et al. 2015

Journal of Nanomaterials

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The use of gold nanoparticles combined with other organic and inorganic materials for designing nanostructured films has demonstrated their versatility for various applications, including optoelectronic devices and chemical sensors. In this study, we reported the synthesis and characterization of gold nanoparticles stabilized with poly(allylamine hydrochloride) (Au@PAH NPs), as well as the capability of this material to form multilayer Layer-by-Layer (LbL) nanostructured films with metal tetrasulfonated phthalocyanines (MTsPc). Film growth was monitored by UV-Vis absorption spectroscopy, atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Once LbL films have been applied as active layers in chemical sensors, Au@PAH/MTsPc and PAH/MTsPc LbL films were used in an electronic tongue system for milk analysis regarding fat content. The capacitance data were treated using Principal Component Analysis (PCA), revealing the role played by the gold nanoparticles on the LbL films electrical properties, enabling this kind of system to be used for analyzing complex matrices such as milk without any prior pretreatment.

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Section: Lbl Filmssupporting

confidence: 89%

Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

Mercante

Scagion

Pavinatto

et al. 2015

Journal of Nanomaterials

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“…These bands are also observed in our LbL films from PAH/ NiTsPc with absorbance maximum shifts to higher energy values. In our work, the absorbance at 615 nm ( max ) was used to monitor the building of multilayers, since PAH does not adsorb in this wavelength [32]. The experimental procedures to obtain the films are essentially the same as those found in our latest work [32].…”

Section: Resultsmentioning

confidence: 98%

“…The amount of mass adsorbed per area unit can be estimated using the Beer-Lambert law from the absorbances and taking into consideration the two faces of the substrate [32]. The immersion time of the substrate in the NiTsPc solution varied during the films growth from 5 to 100 s on PAH layers (3 minutes for all film layers).…”

Section: Resultsmentioning

confidence: 99%

Morphological Structure Characterization of PAH/NiTsPc Multilayer Nanostructured Films

Silva¹,

Brito²,

Tanimoto³

et al. 2011

MSA

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“…For our results, the fast mechanism can be attributed to a fast adsorption mechanism in which the molecules near the PAH monolayer surface diffuse towards it filling the adsorption available sites. The slow mechanism arises from small amount of available sites after a few times and due to electrostatic repulsion between adsorbed molecules and those ones in solution [ 21 ].…”

Section: Resultsmentioning

confidence: 99%

Photoresponsive Wettability in Monolayer Films from Sinapinic Acid

Moura

Gomes²,

Souza³

et al. 2013

The Scientific World Journal

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Sinapinic acid is an interesting material because it is both antioxidant and antibacterial agent. In addition, when illuminated with ultraviolet light, it can exhibit the so-called photodimerization process. In this paper, we report on the investigation of monolayer films from 3,5-dimethoxy-4-hydroxycinnamic acid (sinapinic acid, SinA) deposited onto poly(allylamine hydrochloride), PAH, films. SinA monolayers were prepared by using the layer-by-layer (LbL) self-assembly technique. Adsorption kinetics curves were well fitted by a biexponential function suggesting that the adsorption process is determined by two mechanisms: nucleation and growth of aggregates. By using wetting contact angle analysis, we have found that SinA monolayers exhibit photoresponsive wettability under UV irradiation (365 nm); that is, wettability decreases with increasing UV irradiation time. The photoresponse of wettability was attributed to photodimerization process. This hypothesis was supported by the dependence of surface morphological structure and absorption on UV irradiation time. The mechanism found in the well-known transcinnamic acid crystals is used to explain the photodimerization process in SinA monolayers.

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Adsorption kinetics and charge inversion in layer-by-layer films from nickel tetrasulfonated phthalocyanine and poly(allylamine hydrochloride)

Cited by 8 publications

References 45 publications

Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

Morphological Structure Characterization of PAH/NiTsPc Multilayer Nanostructured Films

Photoresponsive Wettability in Monolayer Films from Sinapinic Acid

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