Polymer Nanostructures

Using the admicellar process and monodisperse spheres organized in an hexagonally packed structure on a flat surface (see Figure below and Reference 1),

Figure 1: Hexagonally packed latex spheres on graphite

We have synthesized polymer in the interstitial sites of the spheres (see Figure 2). Note the differences in scale between Figures 1 and 2; the polymer in Figure 2 has characteristic dimensions on the order of tens of nanometers. The purpose of surfactant is to localize monomer on the surface; the template (i.e. the spheres) mean that surfactant can only adsorb in the interstitial sites. There are other ways to localize monomer to the interstitial sites of spheres (e.g. electrical potential), the interesting thing about this method is that the polymer is much smaller than the interstitial sites, i.e. surfactant does not adsorb very far underneath the spheres. The wall thickness is less than half what you would find for the case where an electric field is used to concentrate monomer in the interstitial sites. Figure 3 shows a schematic of the process. Reference 2 below describes our data, and also contrasts the result for the case where polymer adsorbs in the interstitial sites.

Figure 2: Polyaniline synthesized in the interstitial sites of
adsorbed latex spheres using the admicellar process.