Latex Film Morphology and Electrical Potential Pattern Dependence on Serum Components: A Scanning Probe Microscopy Study

Keslarek, Amauri José; Costa, Carlos Alberto Rodrigues; Galembeck, Fernando

doi:10.1006/jcis.2002.8640

Cited by 13 publications

(8 citation statements)

References 32 publications

(25 reference statements)

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“…The tip apex radius was 28 ± 10 nm, the spring constant 0.5-4.4 N m -1 and the resonance frequency was 45-95 kHz. In air, the images were generated by varying, in the same region, the tip voltage (±1.5 V and ± 3 V) and, for each voltage, the lift height (20,30,40 and 50 nm). For the experiments in N 2 , EFM was carried out using a ±1.5 V tip voltage and a life height of 400 nm.…”

Section: Characterizationmentioning

confidence: 99%

Surface properties of oxidized and aminated multi-walled carbon nanotubes

Silva¹,

Ribeiro²,

Seara³

et al. 2012

J. Braz. Chem. Soc.

104

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A influência de modificação química (por tratamento ácido seguido de funcionalização com trietilenotetramina, TETA) sobre a superfície de nanotubos de carbono de paredes múltiplas (MWCNT) foi estudada qualitativa e quantitativamente. A análise termogravimétrica (TGA) mostrou que, no caso do nanotubo funcionalizado com amina, 29% de perda de massa pode ser atribuída a -C(=O)TETA e grupos funcionais residuais que contêm oxigênio. A espectroscopia de fotoelétrons excitados por raios X (XPS) foi utilizada para observar as funções aminadas e oxigenadas ligadas covalentemente à superfície do nanotubo. As imagens de microscopia de força elétrica (EFM) indicaram que, à medida que se modifica a química superficial dos nanotubos em presença de ar, estes mostram respostas diferentes em função do potencial da ponta. Deslocamentos nos sinais de fase de EFM decrescem quando se modifica a superfície dos tubos com grupos funcionais contendo oxigênio e amina. Em atmosfera seca e inerte de N 2 , as três diferentes superfícies mostraram a mesma resposta à EFM. Além disso, o caráter hidrofílico dos "buckypapers" cresceu na ordem MWCNT < MWCNT-aminado < MWCNT-oxidado.The influence of chemical modification by acid treatment followed by triethylenetetramine (TETA) functionalization on the surface of multi-walled carbon nanotubes (MWCNT) was evaluated, both qualitative and quantitatively. Thermogravimetric analysis (TGA) showed that, in the case of amine-functionalized nanotubes, 29% of mass loss can be attributed to -C(=O)TETA and residual oxygen-containing functional groups. X-ray photoelectron spectroscopy (XPS) was used to observe the oxygenated and aminated functions covalently linked to the nanotube surface. Electric force microscopy (EFM) images indicated that the nanotubes with diverse surface chemistry showed distinct responses to the tip potential in the presence of air. Shifts in EFM phase images decreased when the nanotube surface was modified with oxygen and amine-containing functional groups. In dry and inert N 2 atmosphere, however, the three different surfaces showed the same response to EFM. In addition, the hydrophilic character of the buckypapers increased in the order MWCNT < aminated-MWCNT < oxidized-MWCNT.Keywords: multi-walled carbon nanotubes, triethylenetetramine, surface chemical modification, spectroscopic characterization, electric force microscopy IntroductionAn important historical reference about carbon nanotube (CNT) synthesis is the work of Oberlin et al. in 1976. 1 However, it was not until Iijima's work, in 1991, 2 that CNTs emerged as a key material in the field of nanotechnology due to their extraordinary thermal, electrical and mechanical properties.2-4 However, low dispersibility in organic and inorganic solvents, combined with poor chemical compatibility, has become a major issue. 5,6 Functionalization or chemical modification of CNT, that is, the covalent attachment of atoms or molecules to the surface, has been used to introduce chemical specificity and processability in different environments...

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Section: Characterizationmentioning

confidence: 99%

Surface properties of oxidized and aminated multi-walled carbon nanotubes

Silva¹,

Ribeiro²,

Seara³

et al. 2012

J. Braz. Chem. Soc.

104

View full text Add to dashboard Cite

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“…One might speculate that the local microstructural environment of the water is important for determining whether water can penetrate through a coating to cause substrate corrosion or degradation or whether it remains trapped in isolated pockets within the bulk of the coating or is bound within the polymer phase. When coatings are exposed to water, there are also changes to their microstructures and the growth of water “bubbles” that have been observed with electron microscopy …”

Section: Introductionmentioning

confidence: 98%

Explanations for water whitening in secondary dispersion and emulsion polymer films

Liu

Gajewicz

Rodin

et al. 2016

J Polym Sci B Polym Phys

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The loss of optical transparency when polymer films are immersed in water, which is called “water whitening,” severely limits their use as clear barrier coatings. It is found that this problem is particularly acute in films deposited from polymers synthesized via emulsion polymerization using surfactants. Water whitening is less severe in secondary dispersion (SD) polymers, which are made by dispersing solution polymers in water without the use of surfactants. NMR relaxometry in combination with optical transmission analysis and electron microscopy reveal that some of the water sorbed in emulsion polymer films is contained within nanosized “pockets” or bubbles that scatter light. In contrast, the water in SD polymer films is mainly confined at particle interfaces, where it scatters light less strongly and its molecular mobility is reduced. The addition of surfactant to a SD creates a periodic structure that displays a stop band in the optical transmission. The total amount of sorbed water is not a good indicator of polymers prone to water whitening. Instead, the particular locations of the water within the film must be considered. Both the amount of water and the size of the local water regions (as are probed by NMR relaxometry) are found to determine water whitening. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1658–1674

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“…However, the majority of published work using these techniques has been done on semiconductors or metals. This laboratory used this technique for the examination of dielectric solids, specially those made out of colloid polymers or latexes. − The association between SEPM and analytical electron microscopy (electron energy-loss spectroscopy in the transmission electron microscope, EELS-TEM) allowed the unequivocal identification of polymer charge carriers with ionic constituents such as K + and RSO 4 - ions introduced during the polymerization process. , …”

Section: Introductionmentioning

confidence: 99%

“…This laboratory used this technique for the examination of dielectric solids, specially those made out of colloid polymers or latexes. [15][16][17][18] The association between SEPM and analytical electron microscopy (electron energy-loss spectroscopy in the transmission electron microscope, EELS-TEM) allowed the unequivocal identification of polymer charge carriers with ionic constituents such as K + and RSO 4ions introduced during the polymerization process. 19,20 However, charge patterns were also identified in many thermoplastics that do not contain ionic constituents introduced during the synthesis, thus showing that other types of charge carriers should be considered.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Patterning of a Silica Surface: A New Model for Charge Build-Up on a Dielectric Solid

2005

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The polarization of interdigitated gold electrodes mounted over a silica thin film formed by oxidation of a Si wafer produces reproducible electrostatic patterns with overall excess negative charge, as observed by scanning electric potential microscopy. Domain charge concentrations as high as 76 charge units per square micrometer are obtained when a 5 V difference is applied to the electrodes thus producing fields in the 10(6) V m(-1) range. These patterns vanish when the electrodes are short-circuited and grounded. Characteristic times for pattern formation and relaxation are in the order of 10 min. The results are consistent with a model based on the discharge of H(+) ions at the negative electrodes, leaving behind immobile surface-bound SiO(-) groups and thus showing that chemisorption phenomena are decisive for electrostatic charging of insulators.

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Latex Film Morphology and Electrical Potential Pattern Dependence on Serum Components: A Scanning Probe Microscopy Study

Cited by 13 publications

References 32 publications

Surface properties of oxidized and aminated multi-walled carbon nanotubes

Surface properties of oxidized and aminated multi-walled carbon nanotubes

Explanations for water whitening in secondary dispersion and emulsion polymer films

Electrostatic Patterning of a Silica Surface: A New Model for Charge Build-Up on a Dielectric Solid

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