Design, Fabrication and Implementation of Microfluidics Systems Applied in Chemical Micromixers and Particle Sorters Test

Abstract

In this thesis work, the most recent and relevant work related with microfluidics interms of device fabrication through different techniques with a particular intereston the direct laser writing technique is presented. Direct laser writing techniquewas the used protocol for the fabrication of the microfluidic master masks undertest and the details about the focused light-matter interaction is discussed anddemonstrated.The design and the development of an efficient fabrication protocol of thepolymeric microstructures is presented, discussed and justified. COMSOLMultiphysics simulations were carried out for comparison purposes.The thesis work was focused on two main chips: such as micromixer of chemicalspecies and such as particle sorter. The first one was the main objective of thisthesis work and through which all the experimental procedures and thecorresponding simulations are presented. The designated geometrical shape wasbased on a Y-serpentine with channels of 500μm of width which allowed us to mixtwo fluids. Fluorescence spectroscopy was used such as the measurementtechnique to follow the molar concentration evolution and in this way, acommercial dye was used for this purpose with 0.5x10−6Mol/Lof molarconcentration resolution. COMSOL Multiphysics simulations of the mixing processreproduced well the experimental results which validates these experiments. Theparticle sorter device, this is presented such as perspective of this work becausesome problems in the performance are presented due to limitations on the opticalresolution. Nevertheless, details of device design, fabrication and finally, theparticle tracking application are presented. This microfluidic chip is composed bytwo main sections: the inlets and the sorter section. The first part is composed ofbigger channels than the sorter region, which contains 4 thin channels followed byanother bigger channel that works as outlet. For this microfluidic chip, PMMAparticles with 10μm of diameter were injected inside the chip and their trackingposition along the two sections was performed by video microscopy technique.COMSOL simulations of the fluid behavior were, in addition, carried out andcompared with those experimentally obtained where, it is noticeable that thevelocity of the fluids match well according the experimental observations.Finally, this thesis work presents the full development of a 3D mechanical platformwhich reach 1.25μmof mechanical resolution. The software design that controls itis in addition presented.