Nature abounds with intricate composite architectures composed of hard and
soft materials synergistically intertwined to provide both useful functiona
lity and mechanical integrity. Recent synthetic efforts to mimic such natur
al designs have focused on nanocomposites(1-5), prepared mainly by slow pro
cedures like monomer or polymer infiltration of inorganic nanostructures(6,
7) or sequential deposition(8,9). Here we report the self-assembly of conju
gated polymer/silica nanocomposite films with hexagonal, cubic or lamellar
mesoscopic order using polymerizable amphiphilic diacetylene molecules as b
oth structure-directing agents and monomers. The self-assembly procedure is
rapid and incorporates the organic monomers uniformly within a highly orde
red, inorganic environment. Polymerization results in polydiacetylene/silic
a nanocomposites that are optically transparent and mechanically robust. Co
mpared to ordered diacetylene-containing films prepared as Langmuir monolay
ers(10) or by Langmuir-Blodgett deposition(10), the nanostructured inorgani
c host alters the diacetylene polymerization behaviour, and the resulting n
anocomposite exhibits unusual chromatic changes in response to thermal, mec
hanical and chemical stimuli. The inorganic framework serves to protect, st
abilize, and orient the polymer, and to mediate its function. The nanocompo
site architecture also provides sufficient mechanical integrity to enable i
ntegration into devices and microsystems.