| Summary: | 碩士 === 國立中央大學 === 物理研究所 === 95 === Inspired by the experiment of the fabrication of colloidosome carried out by Dinsmore et al. [1], we are interested in the mechanical strength of the network formed by the aggregation of colloids on a water droplet. Brownian dynamics simulation is applied to simulate slippery diffusion-limited cluster aggregation (slippery DLCA) of nanoparticles on a micron-sized droplet. We study the elasticity of the network on droplets of different sizes and different surface concentration of particles. For higher
concentration of particle on the droplet, there is a greater probability for network to be formed. The elastic modulus increases rapidly after the surface concentration of the particle is greater than some critical concentration. However, we find that although this phenomenon is related to rigidity percolation problem, the simulation result actually indicates that rigidity problem of the aggregate formed by slippery DLCA of nanoparticles on a droplet belongs to a gelation problem. This is because for a larger droplet, the elastic modulus becomes nonzero at lower surface concentration
C and finite-size scaling analysis indicates that it should be nonzero at any finite C for a droplet of infinite radius. Similar behavior is also observed in gelation process in flat space. Furthermore, the fractal dimension of the aggregates formed through this simulation is smaller than 2. Therefore we conclude that rigidity problem of the aggregate formed by slippery DLCA of nanoparticles on a droplet belongs to gelation problem.
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