Polymeric foams with functional nanocomposite cells

A novel strategy for the fabrication of elastomeric poly(dimethylsiloxane) (PDMS) foams with interconnected nanocomposite cells of controlled size is presented. Beads of the natural hydrogel calcium alginate are used as templates for the fabrication of the foams and as initiators for the functionalization of their cells with gold nanoparticles. The hydrogel beads are easily fabricated via external gelation using a fluidic system that permits the control of their size. As a subsequent step, they are assembled in containers where PDMS pre-polymer is poured. As the elastomer cures, the beads shrink releasing the liquid they contain and forming pores in the polymer matrix. By introducing gold precursor solution in the beads, it is possible to develop foams with gold nanoparticles immobilized on the surface of their cells. As the gold ion solution is released by the beads, it chemically interacts with the PDMS, forming nanoparticles locally on the surface of the cavities of the foams. The same procedure can be expanded to various substances resulting in functional foams with localized properties, with applications envisaged in the biomedical field.