Pressure increases with the replica index, so that the size of the circular cavity decreases. Hen... more Pressure increases with the replica index, so that the size of the circular cavity decreases. Hence, the system is ordered by the replica index. At high pressures an optimal packing is produced.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Jun 1, 2008
The adsorption behaviour of soy protein isolate (SPI) is studied at the airwater and an oilwate... more The adsorption behaviour of soy protein isolate (SPI) is studied at the airwater and an oilwater interface. The experimental results are interpreted taking into account a prior structural and electrokinetic characterisation of the SPI in solution. Hence, the SPI forms a ...
Abstract Some properties of spatial confinement of tracer colloidal particles within polyacrylami... more Abstract Some properties of spatial confinement of tracer colloidal particles within polyacrylamide dispersions are studied by means of the well-known dynamic light scattering (DLS) technique. DLS allows obtaining sequences of elapsed times of scattered photons. In this work, the aqueous polyacrylamide dispersion has no crosslinking and the volume fraction occupied by the tracer particles is 0.02 %. Our experimental setup provides two sequences of photons scattered by the same scattering volume that corresponds to two simultaneous experiments (Channel A and Channel B). By integration of these sequences, the intensity time series are obtained. We find that both channels are antipersistent with Hurst exponent, H ∼ 0.43 and 0.36, respectively. The antipersistence of the intensity time series indicates a subdiffusive dynamics of the tracers in the polymeric network, which is in agreement with the time dependence of the tracer’s mean square displacement.
Understanding the effective charge of colloidal particles is crucial to control the stability and... more Understanding the effective charge of colloidal particles is crucial to control the stability and performance of a colloidal system. In particular, the electrostatic interaction potential between the particles determines the stability and thermodynamic properties of electrostatically charged colloidal dispersions. In the case of thermosensitive microgels, which are solvent and ions permeable particles, it is expected that the microgel's size and the number of ions within it are affected by temperature changes. This temperature‐dependent microgel‐solvent ion interchange regulates the microgel net charge and, consequently, the interaction potential. Here, a straightforward experimental method based on conductivity measurements is presented to determine the temperature dependence of the effective net charge of poly‐N‐isopropylacrylamide, PNIPAM, microgels under different salinity conditions. Our results show that the net charge of the microgel decreases with increasing temperature....
This work studies the kinetics of crystallization of charged microgels suspensions of Poly-N-Isop... more This work studies the kinetics of crystallization of charged microgels suspensions of Poly-N-Isopropylacrylamide (PNIPAM) at low ionic strength. The liquid-crystal transition is induced by suddenly decreasing the temperature of the microgel dispersion, and the crystallization process is monitored by measuring the temporal evolution of the static structure factor of the dispersion using light scattering. We find that the crystal growth rate, indicated by the temporal evolution of the crystallinity factor, strongly depends on the quenching temperature.
Revista Tendencias en Docencia e Investigación en Química. Año 6, número 6 (enero-diciembre de 2020). ISSN: 2448-6663, 2020
La problemática de las enfermedades biológico-infecciosas causadas por el consumo de aguas contam... more La problemática de las enfermedades biológico-infecciosas causadas por el consumo de aguas contaminadas se encuentra en un estado alarmante, por lo que día a día se buscan nuevas técnicas para la erradicación de bacterias patógenas presentes en agua, una gran alternativa para la eliminación de dichos contaminantes es el uso de micromateriales metálicos de fácil recuperación. Por lo que, en este trabajo se presenta una metodología para obtener micropartículas de magnetita cubiertas con plata (core@shell) mediante síntesis verde, con la finalidad de evaluar su efecto inhibitorio sobre de Bacillus subtilis y Escherichia coli en presencia de dichas micropartículas. Los experimentos fueron evaluados en un lapso de 24 horas, donde se encontró que las core@shell inhiben en su totalidad el desarrollo bacteriano, demostrando tener un efecto bactericida. Debido al centro paramagnético de las core@shell su recuperación se lleva a cabo mediante un imán de forma rápida y eficiente.The problem of biological-infectious diseases caused by the consumption of contaminated water is in an alarming state, every day new techniques are sought for the eradication of pathogenic bacteria present in water, a great alternative for the elimination of these contaminants is the use of metallic micromaterials. This paper presents a methodology to obtain magnetite microparticles covered with silver (core@shell) by green synthesis, in order to evaluate the effect of inhibition of bacterial growth of Bacillus subtilis and Escherichia coli in the presence of the microparticles. The experiments were evaluated in a 24-hour period, where was found that core@shell completely inhibit bacterial development, proving to have a bactericidal effect. Due to the paramagnetic center of the core@shell, its recovery is carried out by means of a magnet, quickly and efficiently
The addition of small charged particles to a dispersion of bigger charged colloids produces a dep... more The addition of small charged particles to a dispersion of bigger charged colloids produces a depletion effect greater than that caused by the addition of neutral ones.
Pressure increases with the replica index, so that the size of the circular cavity decreases. Hen... more Pressure increases with the replica index, so that the size of the circular cavity decreases. Hence, the system is ordered by the replica index. At high pressures an optimal packing is produced.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Jun 1, 2008
The adsorption behaviour of soy protein isolate (SPI) is studied at the airwater and an oilwate... more The adsorption behaviour of soy protein isolate (SPI) is studied at the airwater and an oilwater interface. The experimental results are interpreted taking into account a prior structural and electrokinetic characterisation of the SPI in solution. Hence, the SPI forms a ...
Abstract Some properties of spatial confinement of tracer colloidal particles within polyacrylami... more Abstract Some properties of spatial confinement of tracer colloidal particles within polyacrylamide dispersions are studied by means of the well-known dynamic light scattering (DLS) technique. DLS allows obtaining sequences of elapsed times of scattered photons. In this work, the aqueous polyacrylamide dispersion has no crosslinking and the volume fraction occupied by the tracer particles is 0.02 %. Our experimental setup provides two sequences of photons scattered by the same scattering volume that corresponds to two simultaneous experiments (Channel A and Channel B). By integration of these sequences, the intensity time series are obtained. We find that both channels are antipersistent with Hurst exponent, H ∼ 0.43 and 0.36, respectively. The antipersistence of the intensity time series indicates a subdiffusive dynamics of the tracers in the polymeric network, which is in agreement with the time dependence of the tracer’s mean square displacement.
Understanding the effective charge of colloidal particles is crucial to control the stability and... more Understanding the effective charge of colloidal particles is crucial to control the stability and performance of a colloidal system. In particular, the electrostatic interaction potential between the particles determines the stability and thermodynamic properties of electrostatically charged colloidal dispersions. In the case of thermosensitive microgels, which are solvent and ions permeable particles, it is expected that the microgel's size and the number of ions within it are affected by temperature changes. This temperature‐dependent microgel‐solvent ion interchange regulates the microgel net charge and, consequently, the interaction potential. Here, a straightforward experimental method based on conductivity measurements is presented to determine the temperature dependence of the effective net charge of poly‐N‐isopropylacrylamide, PNIPAM, microgels under different salinity conditions. Our results show that the net charge of the microgel decreases with increasing temperature....
This work studies the kinetics of crystallization of charged microgels suspensions of Poly-N-Isop... more This work studies the kinetics of crystallization of charged microgels suspensions of Poly-N-Isopropylacrylamide (PNIPAM) at low ionic strength. The liquid-crystal transition is induced by suddenly decreasing the temperature of the microgel dispersion, and the crystallization process is monitored by measuring the temporal evolution of the static structure factor of the dispersion using light scattering. We find that the crystal growth rate, indicated by the temporal evolution of the crystallinity factor, strongly depends on the quenching temperature.
Revista Tendencias en Docencia e Investigación en Química. Año 6, número 6 (enero-diciembre de 2020). ISSN: 2448-6663, 2020
La problemática de las enfermedades biológico-infecciosas causadas por el consumo de aguas contam... more La problemática de las enfermedades biológico-infecciosas causadas por el consumo de aguas contaminadas se encuentra en un estado alarmante, por lo que día a día se buscan nuevas técnicas para la erradicación de bacterias patógenas presentes en agua, una gran alternativa para la eliminación de dichos contaminantes es el uso de micromateriales metálicos de fácil recuperación. Por lo que, en este trabajo se presenta una metodología para obtener micropartículas de magnetita cubiertas con plata (core@shell) mediante síntesis verde, con la finalidad de evaluar su efecto inhibitorio sobre de Bacillus subtilis y Escherichia coli en presencia de dichas micropartículas. Los experimentos fueron evaluados en un lapso de 24 horas, donde se encontró que las core@shell inhiben en su totalidad el desarrollo bacteriano, demostrando tener un efecto bactericida. Debido al centro paramagnético de las core@shell su recuperación se lleva a cabo mediante un imán de forma rápida y eficiente.The problem of biological-infectious diseases caused by the consumption of contaminated water is in an alarming state, every day new techniques are sought for the eradication of pathogenic bacteria present in water, a great alternative for the elimination of these contaminants is the use of metallic micromaterials. This paper presents a methodology to obtain magnetite microparticles covered with silver (core@shell) by green synthesis, in order to evaluate the effect of inhibition of bacterial growth of Bacillus subtilis and Escherichia coli in the presence of the microparticles. The experiments were evaluated in a 24-hour period, where was found that core@shell completely inhibit bacterial development, proving to have a bactericidal effect. Due to the paramagnetic center of the core@shell, its recovery is carried out by means of a magnet, quickly and efficiently
The addition of small charged particles to a dispersion of bigger charged colloids produces a dep... more The addition of small charged particles to a dispersion of bigger charged colloids produces a depletion effect greater than that caused by the addition of neutral ones.
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