Models and Systems for the control of two-phase processes in microfluidics

Microfluidics is a novel and promising scientific field research whose progresses are aimed to the development of the Lab-On-Chip (LOC) systems. The strong point of the microfluidics is the ability to miniaturize and integrate one or several laboratory functions on the same device, to have a portable and user-friendly instrument. Most applications require accurate measures and control within the microfluidic channels. In this thesis, the optical techniques were adopted to monitor, sensing and control the processes, leading to the research area of optofluidics that are based on the integration of fluidics and optics. To reduce the cost, to develop these devices and, at the same time, to have the optics and fluidics parts integrate in the same device, the 3D Printing technology based on the Poly(dimethyl-siloxane) (PDMS) is proposed. All these aspects were addressed considering the two-phase flow (named slug) generated by the interaction of two immiscible fluids, a very common condition in bio-chemical applications. The methodological aspects were discussed in the first part of the thesis, starting from the extraction of parameters for the flow characterization, to their use for the flows real-time modelling and control schemes development; the second part investigates aspects faced for the realization of micro-optical flow detector by using the 3D Printing technology.