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Sousa, Maria P.; Azeredo, Joana; Feijó, J.; Oliveira, Rosário

doi:10.1023/a:1018400619440

Cited by 30 publications

(5 citation statements)

References 4 publications

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“…In eq 12, subscripts s an p refer to sphere and plate, κ is the inverse Debye screening length, A H = 1.4 × 10 -20 J is the Hamaker constant based on Lifshitz theory, d is the distance between surfaces, Γ = tanh (e ψ/4 k B T ), ε is the dielectric constant, e is the electron charge, and ψ is the surface potential for a sphere or plate. On the basis of the surface charge density reported for the particles and electrophoretic mobility experiments, ψ s is in the range of 80−100 mV, and ψ p is in the range of 20−50 mV . By applying the criteria for colloidal stability ( W = d W /d D = 0) to eq 12, we estimated a critical KCl concentration of ∼80 mM for particle−substrate coagulation.…”

Section: Resultsmentioning

confidence: 99%

Surface-Guided Templating of Particle Assemblies Inside Drying Sessile Droplets

2007

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The particles suspended inside evaporating sessile droplets can be assembled into microscopic objects with long-ranged ordered structure. The air-water droplet interface guides the assembly and determines the shape of the resulting micropatches. We report the results of a systematic study of the mechanism of interface-templated assembly on substrates of controlled contact angle. The kinetics of drying were examined by measurements of droplet profiles, and it was found that the rate matched diffusion-limited evaporation well. The shape of the droplets and of the resulting assemblies was correlated to the dynamics of the receding contact line. The effects of major parameters controlling the process, including contact angle, particle concentration, and electrolyte, were investigated in detail. A variety of micropatch shapes were observed and categorized within the parameter space. The in-depth characterization of the process allowed the optimization of the assembly and the formulation of protocols for the deposition of nanostructured patches of different diameter, thickness, and shape.

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Section: Resultsmentioning

confidence: 99%

Surface-Guided Templating of Particle Assemblies Inside Drying Sessile Droplets

2007

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“…It was also shown that hydrophobicity plays an important role in initial adhesion of pathogenic bacteria [3]. Hydrophobicity has also been associated with fouling in marine environments [4], the adhesion of microorganisms to minerals [5] and to polymeric supports [6].…”

Section: Introductionmentioning

confidence: 99%

Exopolymers in bacterial adhesion: interpretation in terms of DLVO and XDLVO theories

Azeredo

Visser

Oliveira

1999

Colloids and Surfaces B: Biointerfaces

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Exopolymers have an important role in bacterial adhesion and are associated with irreversible adhesion. Moreover, they can coat surfaces enhancing or avoiding bacterial colonisation. To study the role of exopolymers in the adhesion of bacteria to glass, three mutants of Sphingomonas paucimobilis (which are high (TR), medium (CV) and low (F72) exopolymer producers), were used. The adhesion tests were performed in phosphate saline buffers and in solutions of the exopolymer produced by each mutant. The DLVO theory was able to explain the results in phosphate saline buffers, although this theory could not explain the results obtained in the presence of the exopolymer. The XDLVO theory enabled the interpretation of the results in the presence of the exopolymer, where hydrophobic interactions played an important role. However, polymeric interactions that are not taken into account in these two theories are also expected to be determinant in the adhesion process.

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“…The water-rich areas of the world are truly the richest places on Earth. 7 Particularly, a lot of synthetic materials such as poly(vinyl alcohol), [8][9][10][11] poly(methyl methacrylate), 12 polypropylene, 13 polystyrene, 14 PU, [15][16][17][18] and modified PU [19][20][21] have been used. In the case of ocean and river quality, such pollution is primarily caused by discharge of inadequately treated industrial and municipal wastewaters.…”

Section: Introductionmentioning

confidence: 99%

“…However, in biosystems immobilization, the factors that influence the choice of the method to be used are generally empirical. 7 Particularly, a lot of synthetic materials such as poly(vinyl alcohol), [8][9][10][11] poly(methyl methacrylate), 12 polypropylene, 13 polystyrene, 14 PU, [15][16][17][18] and modified PU [19][20][21] have been used. As of now, polyurethanes (PU) are one of the most versatile materials in the world.…”

Section: Introductionmentioning

confidence: 99%

Semiconducting polyurethane/polypyrrole/polyaniline for microorganism immobilization and wastewater treatment in anaerobic/aerobic sequential packed bed reactors

Antonio‐Carmona

Martínez-Amador

Martínez‐Gutiérrez

et al. 2015

J of Applied Polymer Sci

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The development of new materials for microorganism immobilization is very important in wastewater treatment. In this work polyurethane (PU) foams were modified polymerizing pyrrole and aniline onto their surface by chemical oxidization to obtain polyurethane/polypyrrole (PU/PPy), polyurethane/polyaniline (PU/PANI), and PU/(PPy‐co‐PANI) supports which were used to immobilize microorganisms for municipal wastewater treatment in batch mode and continuous flow using two sequential (anaerobic/aerobic) packed bed reactors (PBR) varying the total hydraulic retention time (HRT). The supports were characterized by Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) and tested in chemical oxygen demand (COD) removal during treatment of a municipal wastewater. It was observed from SEM analysis that globular nanostructures of PPy and PPy‐co‐PANI were formed onto the PU surface with average diameters between 100 and 300 nm, which are typical of aqueous polymerization of pyrrole monomer; however irregular nanostructures were observed when PANI was homopolymerized onto the PU foam. Batch wastewater treatment after 14 days showed COD removal efficiencies of 77%, 69%, 78%, and 80% for PU foam, PU/PPy, PU/PANI, and PU/(PPy‐co‐PANI), respectively; which was explained as a function of polymers morphology deposited onto the PU foam surface. Also it was observed from the sequential PBR that for 24 h and 36 h of HRT, 80 and 90% of COD removal can be achieved; respectively.© 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42242.

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Cited by 30 publications

References 4 publications

Surface-Guided Templating of Particle Assemblies Inside Drying Sessile Droplets

Surface-Guided Templating of Particle Assemblies Inside Drying Sessile Droplets

Exopolymers in bacterial adhesion: interpretation in terms of DLVO and XDLVO theories

Semiconducting polyurethane/polypyrrole/polyaniline for microorganism immobilization and wastewater treatment in anaerobic/aerobic sequential packed bed reactors

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