This thesis mainly focuses on two topics: the electrorheological effect from dipolar water filaments and multiple droplet reaction and three dimension temperature mapping based on microfluidic method. In the first section, the field induced water filament is studied both theoretically and experimentally. Based on microscopic mechanism of the GER effect, a phenomenological model is raised to describe spontaneous and field-induced filaments formation at urea/water-silicone oil interface, giving the prediction that the field induced molecular filaments of water could become macroscopic in length, like mm. We have turned to use the molecular dynamics (MD) simulation for further examination. The simulated results have confirmed the existence of such filaments and resulted molecular e...[ Read more ]

This thesis mainly focuses on two topics: the electrorheological effect from dipolar water filaments and multiple droplet reaction and three dimension temperature mapping based on microfluidic method. In the first section, the field induced water filament is studied both theoretically and experimentally. Based on microscopic mechanism of the GER effect, a phenomenological model is raised to describe spontaneous and field-induced filaments formation at urea/water-silicone oil interface, giving the prediction that the field induced molecular filaments of water could become macroscopic in length, like mm. We have turned to use the molecular dynamics (MD) simulation for further examination. The simulated results have confirmed the existence of such filaments and resulted molecular electrorheological effect. Experiments have been conducted with parallel-plate channel for different systems: water-silicone oil and water decane. The measured results indicate that a pressure difference would occur under the applied electric field for water-silicone oil case while no such effect for water-decane case. The observed electrorheological effect gives a convincing demonstration of formation of water molecular filaments.

An improved cartridge droplet generation device is introduced in the second section. The droplet volume, distance, number and droplet sequence can be precisely controlled by a programmed controller. Our experiments of droplet screening and aggressive droplet reaction imply that we have provided a simple model to develop a computer-aided sample-in, result-out system that utilizes nano- to picoliter droplets for low reagent consumption and high throughput. Moreover, a new functional material, RAP, has been developed for 3D temperature monitoring of microfluidic chip. Outstanding solvent, thermal stability and photo stability of this material permits accurate and rapid temperature measurement of local temperature surrounding a nanoliter droplet trapped inside a RAP chamber. This new thermometric methodology is sufficient to characterize vigorous reaction in nL droplet which is much safer and later on recognized that behave distinctively from bench-top size experiments in mL volume.