Alejandro Londoño

Alejandro's research is directed at predicting the behavior of liquid crystals when nanoparticles are present. Specific applications of this project include liquid crystal detection of endotoxins at extremely low concentrations and liquid crystal mediated assembly of particles at the nano-scale. For the case of endotoxin sensors, experimental results suggest that liquid crystals tend to undergo a phase change when endotoxins are present. Due to the small scale and complexity of the problem, information available from experiments is still not sufficient to achieve a complete understanding. Numerical simulation is used to understand the physics governing the different liquid crystal phases and how to control and predict these transitions. For the case of liquid crystal-mediated assembly of nanoparticles, experiments have shown the ability of liquid crystals to organize particles in networks. Once these networks have been formed, they can be made permanent via polymerization, paving the way for novel assembly applications. Similar to the case of the endotoxins, a better grasp of the governing phenomena is still needed in order to fully develop the techniques. Numerical simulations are used as a tool to predict particle network distribution as a function of process parameters and material properties. Simulations of LC -particle systems are performed using continuum techniques. His current work involves the combination of these techniques with a Monte Carlo approach in order to ensure a comprehensive exploration of the energy landscape.