Publicação
Adsorption of colloidal particles on mobile rafts
| Resumo: | Colloidal particles trapped at oil-water interfaces interact through long-range capillary forces resulting from the deformation of the interface. As a result, kinetically trapped structures are obtained and expected quasi-2D thermodynamic phases are rarely obtained. A scheme was recently proposed to avoid such strong particle-particle interactions and to obtain a fully ergodic quasi-2D colloidal dynamics. The idea is to adsorb DNA-coated colloidal particles on complementary DNA patches that are diffusing on the surface of the oil droplets. Here, we develop a theoretical model that replicates the relevant physical properties of the experimental system. We perform an extensive numerical study of the model using a kinetic Monte Carlo algorithm. We find that the coverage, for an earlier stage of the evolution, does not depend strongly on the diffusion coefficient. However, as time evolves differences become evident. We also observe that as the system reaches jamming, the number of parameters that describe the coverage evolution can be reduced. We supplement this study with an analytical approach using a mean-field approximation. With it, we are able to reach closed form equations that describe the time evolution of the density of adsorbed particles and patches, and show that the numerical data follows the same functional dependency. We also show that our results are able to reproduce, qualitatively, what is seen in the experiments. Finally, we use a one-dimensional continuum model to study numerically the irreversible ad- sorption of particles on the patches, with the focus on the possible configurations created due to the random sequential adsorption. Here, we study how the number of adsorbed particles on the patch de- pends on the ratio between their respective sizes. We support this study with an analytical approach, which enumerates the possible configurations of the model for certain patch sizes. We show that the analytical results are in very good agreement with the numerical ones. |
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| Autores principais: | Pinto, Diogo Estêvão Pereira |
| Assunto: | Colloidal particles Systems far from equilibrium Random sequential adsorption Teses de mestrado - 2017 |
| Ano: | 2017 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Colloidal particles trapped at oil-water interfaces interact through long-range capillary forces resulting from the deformation of the interface. As a result, kinetically trapped structures are obtained and expected quasi-2D thermodynamic phases are rarely obtained. A scheme was recently proposed to avoid such strong particle-particle interactions and to obtain a fully ergodic quasi-2D colloidal dynamics. The idea is to adsorb DNA-coated colloidal particles on complementary DNA patches that are diffusing on the surface of the oil droplets. Here, we develop a theoretical model that replicates the relevant physical properties of the experimental system. We perform an extensive numerical study of the model using a kinetic Monte Carlo algorithm. We find that the coverage, for an earlier stage of the evolution, does not depend strongly on the diffusion coefficient. However, as time evolves differences become evident. We also observe that as the system reaches jamming, the number of parameters that describe the coverage evolution can be reduced. We supplement this study with an analytical approach using a mean-field approximation. With it, we are able to reach closed form equations that describe the time evolution of the density of adsorbed particles and patches, and show that the numerical data follows the same functional dependency. We also show that our results are able to reproduce, qualitatively, what is seen in the experiments. Finally, we use a one-dimensional continuum model to study numerically the irreversible ad- sorption of particles on the patches, with the focus on the possible configurations created due to the random sequential adsorption. Here, we study how the number of adsorbed particles on the patch de- pends on the ratio between their respective sizes. We support this study with an analytical approach, which enumerates the possible configurations of the model for certain patch sizes. We show that the analytical results are in very good agreement with the numerical ones. |
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