Foams in microfluidics

Foams are investigated to be self-assembled materials exhibiting interesting photonic properties. We experimentally build 3D foams by packing air bubbles in aqueous solution containing a monomer. The bubbles are produced in a PDMS (Polydimethylsiloxane) microfluidic chip and directly assembled in a microfluidic channel giving birth to highly tunable 3D foam. Indeed, by varying fluid pressures, the foam composition and fabrication process, we manage to sharply control bubbles production and thereby govern the structural properties of the obtained material: porosity, pores size, connectivity and polydispersity. Electromagnetic simulations are then performed to study wave propagation in such materials over an important range of frequencies and different relevant transmission regimes are distinguished.