By Hessam Mehr
We have made an exciting new composite material in our lab. In a composite material, two or more chemicals are finely mingled without changing their identity, just like raisins and dough in raisin cookies, to make a new and interesting material!
In this case, the dough is made of glass full of tiny, twisted pores and the raisins are a plastic material, or polymer, called PPV. Short for poly(p-phenylene vinylene), PPV is special because it gives off a beautiful green glow under blue light, a phenomenon known as fluorescence.
Working with PPV is tricky because it doesn’t melt or soften up in solvents. This means that in order to mix the glass and PPV together, like the dough and raisins, there is no easy way of taking a piece of PPV and squeezing it into the tiny holes in the glass. We had to use a trick discovered by chemists in 1998 to put the molecular building blocks of PPV, or its monomers, together right inside the holes.
Like when using a mould, the tiny pieces of PPV that we form this way have the same twisted shape as the pores they started life in.
Novel PPV/Mesoporous Organosilica Composites: Influence of the Host Chirality on a Conjugated Polymer Guest. Mehr, S. H. M.; Giese, M.; Qi, H.; Shopsowitz, K. E.; Hamad, W. Y.; MacLachlan, M. J. Langmuir 2013, 29, 12579–12584.