Laser Ablation for Microfluidic Applications: Simulation and Experimental Analysis of Microfluidic Geometries Fabricated with an Excimer Laser Incorporating a Novel Intelligent Pinhole Mask
MetadataShow full item record
This item's downloads: 489 (view details)
Excimer lasers have proven to be a useful tool for the precision removal of thin layers of polymer material. With the advent of polymer microfluidics, excimer lasers may have a role to play in the production of small volume prototype devices. However, there are limitations associated with excimer machining, in particular, scanning laser ablation through a static mask. This thesis presents a method to overcome these limitations using a dynamic variable aperture in place of the static mask on the excimer laser system. The dynamic, or intelligent, pinhole mask (IPM) can be used to overcome some of the drawbacks to traditional scanning laser ablation. Beam reconfiguration techniques are developed and used to produce complex microchannel geometries. A validated predictive model, incorporating variables for the laser, IPM, scanning stage and material ablation rate, greatly reduces the time required on the laser, thus reducing the design to final device realisation time. Using the laser system and predictive model, microfluidic mixing channels are developed. The mixers are based on 2D and 3D baffle geometries producible by precise control of the IPM opening during the machining process. The mixing channels are first developed offline using a combination of the predictive model and computational fluid dynamics (CFD) to refine channel geometry prior to the fabrication step. A designed experiment is used to reduce the number of CFD simulations required in order to reach the optimised microchannel geometry. The mixers use the principle of induced chaotic advection to combine initially separate fluid streams efficiently over a short distance. Both mixers demonstrate high mixing efficiency in comparison to a standard T-mixer over a Reynolds number (Re) range from 0.1 to 20. At a Re of 0.1, 90% mixing is achieved in a path length of 32 mm and 7 mm, for the 2D and 3D mixers, respectively. This represents an improvement in performance over a standard T-mixer of 20% for the 2D mixer and 82.5% for the 3D mixer. Finally, the 3D mixer is incorporated into a functional microfluidic device prototype. Using this prototype, on-chip hybridisation of a synthetic bacterial sample is successfully demonstrated.
This item is available under the Attribution-NonCommercial-NoDerivs 3.0 Ireland. No item may be reproduced for commercial purposes. Please refer to the publisher's URL where this is made available, or to notes contained in the item itself. Other terms may apply.
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Collins, Adam (2016-02-04)Laser scribing of thin glass has proven problematic due to inefficient optical absorption and difficulty achieving economical processing speeds while maintaining edge quality. Laser processing of glass is pertinent to touch ...
Physical and bio cellular response of laser induced periodic surface structures formed using a femtosecond laser on a platinum alloy McDaniel, Clare (2015-09-30)Minimally invasive implantable medical devices represent a major advance in the treatment of obstructive coronary artery disease with stent implantation becoming the standard coronary angioplasty procedure. Such devices ...
Dependence of mechanical properties of polyamide components on build parameters in the SLS process Lohfeld, Stefan; McHugh, Peter E.; Caulfield, Brian (Elsevier, 2007)Customised properties of parts manufactured using the selective laser sintering process are achievable by variation of build parameters. The energy density, controlled by laser power, distance between scan lines and speed ...