Supramolecular effects on formation of CaCO3 thin films on a polymer matrix

We here report the use of carboxylated polyrotaxanes as supramolecular templates for the formation of CaCO3 thin films. Polyrotaxanes consisting of carboxylated alpha-cyclodextrins (alpha-CD-COOH) and poly(ethylene glycol) have been obtained as an inducer of CaCO3 crystals. Poly(vinyl alcohol) has been used as a matrix to interact with the polyrotaxanes for this crystallization. These polyrotaxanes induce the formation of CaCO3 thin films, while the simple mixture of monomeric alpha-CD-COOH and capped poly(ethylene glycol) only leads to the formation of granular crystals. The assembled carboxyl groups due to the construction of the polyrotaxane structure play an essential role for the development of CaCO3 thin films. Moreover, morphology and orientation of the obtained CaCO3 thin films are dependent on the amount of alpha-CD-COOH incorporated into the polyrotaxane structure. This approach to the use of supramolecular templates will bring new designs for hybrid materials.