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The major part of microfluidic devices nowadays consists of a dense material that defines the fluidic structure. A generic fabrication method enabling the production of completely porous micro devices with user-defined channel networks is developed. The channel walls can be used as a (selective) barrier for transport. In this conceptual article the focus is on the opportunities offered by this approach. Fabrication method and applicable materials are briefly discussed. Two applications of porous micro devices are shown: a micro gas-liquid contactor and a porous channel emulsificator that can be used to make monodispersed droplets. For both devices a short comparison with alternative concepts is drawn. Finally, key areas for the presented technology are addressed.

Conclusions:The experimentally determined values of the power indices x and c describing dependence of conductivity r~f v and permittivity e~f ±c on AC frequency f in polyisoprene-carbon nanocomposite in the vicinity of percolation threshold are consistent with the general scaling principle of the percolation theory v + c = 1. The obtained values of v and c are in agreement with the mechanism of inter-cluster polarisation.The experimentally observed deviation from the relation e~|M-M C | ±s of the statistical percolation theory at carbon concentrations above the percolation threshold M > M C may be a result of particle agglomeration and deviation from statistical distribution. The asymmetric and branching shapes of particle clusters cause strong local electric fields in the matrix between clusters providing additional contribution to the dielectric permittivity.