Freeform microfluidic structures embedded in 3D laser printed centimeter-scale objectsTuesday (23.06.2020) 10:50 - 11:10 Room 1
Recent years, there is a rapidly increasing demand for developing large-scale microfluidic systems with 3D flexible configurations, since they provide great potentials for fostering high-performance continuous-flow manufacturing as well as biomimetic manufacturing. Among many commonly used substrates for microfluidic systems, glass materials have several distinguished advantages for practical applications such as wide-range transparency, good chemical inertness, and good biocompatibility. Currently, one of the most representative methods to prepare 3D glass microfluidic structures is femtosecond (fs) laser microfabrication. With fs laser irradiation, 3D hollow microchannels with complex geometries can be fabricated in glass using either laser assisted chemical etching or liquid-assisted laser drilling. However, some fabrication challenges still remain when the required size of the processing workpiece reaches to several centimeters. For instance, with the increase of processing depth, the effects of laser-induced aberration cannot be neglected, which seriously deteriorates the fabrication resolution. In addition, with prolonging the fabrication length of channel, the homogeneity of the channel becomes worse especially when wet chemical etching is applied. Herein, we demonstrate our recent progress on fabrication of 3D large-scale all-glass microfluidic structure at a micrometer-scale resolution. Freeform 3D microfluidic structures embedded in 3D printed glass centimeter-scale objects have been manufactured using the hybrid laser microfabrication scheme based on the combination of ultrashort pulse laser-assisted chemical etching of glass, 3D laser subtractive glass printing, and carbon oxide (CO2) laser-induced glass melting. To fabricate 3D uniform glass microchannels with centimeter-scale length, introduction of a string of extra-access ports along the microfluidic channels are adopted for ensuring homogeneous fabrication of the channels during the chemical etching. Then, controllable sealing of those ports has been achieved using CO2 laser irradiation for all-glass structure manufacturing. Moreover, 3D laser subtractive glass printing enables rapid manufacturing of macroscale glass objects with desirable shapes and a high precision down to several tens of micrometers due to two unconventional characteristics, i.e., depth-independent focusing and polarization-insensitive etching in the interaction of loosely focused ps laser pulses with fused silica.