Hot-embossing of polymeric micro-structures devices.
Teo, Benjamin Qingliang.
Date of Issue2009
School of Mechanical and Aerospace Engineering
With advancement in technology, many devices are now made smaller, more efficient and yet remain cost effective. This is the same for microfluidic devices that are used for lab on chip devices and other laboratory tests. Previously made using silicon, they are costly and require complex method of lithography fabrication. Research has shown that polymers can be used to fabricate the same chip using simpler methods such as hot embossing at a much lower cost. This project aims to use the statistical method ANOVA to evaluate and optimize the hot-embossing parameters in order to fabricate PMMA and COC micromixers with good replication accuracy from a metallic glass mold insert that has the micromixer pattern micro-machined on its surface. Firstly, the thermal characteristics of each polymer were obtained experimentally and a series of experiments were carried out according to the Design of Experiment (DOE). Using the analysis of variance (ANOVA), the significant parameters were singled out for optimization. They are, embossing temperature, embossing time, re-embossing pressure and re-embossing time. During optimization, the values for each significant parameter were varied and analyze to obtain the ideal value that would emboss samples with the best accuracy. Lastly, repeatability tests were carried out using the optimized parameter values that have been established. The confocal imaging profiler as well as scanning electron microscopy was used to analyze all the embossed samples and measurements of the images were made using the Digitizer software. Results show that the newly optimized embossing parameters were able to produce PMMA substrates with better replication accuracy and up to 6% lower shrinkage as compared to results previously obtained. On the other hand, COC substrates only managed marginal improvement in two of five measurement points.
Final Year Project (FYP)
Nanyang Technological University