4M Knowledge base - papers
Zhigang Zhu, Xueyong Wei and Kyle Jiang
Centre for MicroEngineering and NanoTechnology, School of Engineering, The University of Birmingham, B15 2TT, UK
This paper presents a soft lithography technique to fabricate alumina microcomponents. The process uses elastomer polydimethysiloxane (PDMS) and makes the green patterns in tact after demoulding. The five steps of the soft lithography process are: (I) fabricating thick SU-8 moulds using UV photolithography; (II) producing PDMS soft mould from the SU-8 masters; (III) making aqueous high solids loading alumina suspension; (IV) filling patterned PDMS moulds with the aqueous alumina suspension; (V) demoulding and sintering. The rheological properties (Zeta potential and viscosity) of aqueous alumina suspensions was characterized in relation with varying pH values and concentration of dispersant (D-3005). The optimal parameters of the alumina suspension for the mould filling have been achieved as pH value = 11; concentration of dispersant (D-3005) = 0.05 g/ml; amount of binder (B-1000+ B-1007) = 0.75%, the highest solid loading = 70 wt.%. After pressurised mould filling, the complete, dense and freestanding microcomponents have been achieved by using 70wt.% alumina suspension and optimum fabrication technique, while the overall shrinkage is found as ca. 22%.
T. Brenner, C. Müller, H. Reinecke, R. Zengerle, and J. Ducrée
IMTEK – University of Freiburg, Georges-Koehler-Allee 106, D-79110 Freiburg, Germany
We established an integrated prototyping chain for rapid fabrication of microfluidic chips in polymers comprising fabrication of masters made from elastomers, replication into polymers by soft embossing, surface modification and thermal sealing. Our techniques enable rapid and precise fabrication of fully functionalized microfluidic chips featuring typical minimum lateral dimensions of 50 μm and aspect ratios smaller than one.
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