Escrita direta a laser em material polimérico

Abstract

The fabrication of microfluidic devices in polymeric material can be done by several techniques already known from the literature, in search of speed in the fabrication process combined with the quality of the devices the direct laser writing technique showed to be more promising. This work presented the conditions found in the PMMA fabrication process with the use of a CO2 power laser with a wavelength of 10.6μm to obtain low cost devices. A literature review of the works that have fabricated devices using the direct laser writing process on polymeric materials was performed. In the manufacturing process of the devices found some defects in the workpiece. Recent research has shown that in the PMMA combustion process several effects can cause defects on the surface of the machined plate, such as the formation of protuberances on the walls of the channels that interfere with one of the main characteristics of microfluidic devices, such as laminar flow. Thermal and optical analysis were used in order to understand the behavior of the laser interaction with matter. The case studies showed a control of some fabrication processes, starting from the laser parameters combined with the number of passes that reduced the amount of resolidified material on the material surface. Alternative techniques were also used to improve the quality of the channels, such as the solvent reflow technique that reduced the amount of resolidified material on the channel walls and improved the optical transparency of the PMMA. The results found in recent work showed that there was no pore formation and swelling in the walls of the microchannels in PMMA with a molecular weight of 96.7kDa, but defects were found in materials with molecular weights of 120kDa, 350kDa, and 996kDa.