Tailoring of free standing microchannels structures via microtemplating

The preparation of ceramic microchannel structures from powder based material is a time consuming, expensive or inflexible process. This work demonstrates microtemplating – a new reliable and economical fabrication method for preparing ceramic alumina self-supporting microchannels with diameters from 10 to 1000 μm. The basis for this method is the controlled dip-coating of a sacrificial polymeric fiber template with suspensions containing sinterable particles. Subsequent sintering results in self-supporting ceramic microchannels. Thermal behavior of a microtemplate is critical for achieving self-supporting microchannels. We used polyamide, keratin, para-aramide, polypropylene, and polyimide fibers to set models of microtemplate thermal behavior. We found that the negative influence of thermal expansion and gas production could be eliminated by microtemplates with hollow and porous internal structure. Furthermore we show flexibility of the green stage procedure on an alumina microfluidic loop and a multichannel system with gradient porosity. The microtemplating is demonstrated to be an inexpensive and flexible process.

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► The controlled dip-coating of a sacrificial polymeric fiber template with suspensions containing sinterable particles.
► Microtemplating need the selection of suitable template material and/or internal microtemplate design.
► A successful strategy of internal design is to use hollow and porous fibers as microtemplates.
► Microtemplating offers the possibility to use various particles and benefit from multiple coating and mechanical flexibility of the green stage procedure.