Polymerizing Monomer within Zeolite Cavities

A different approach was initiated by Frisch and Xue [62, 140] to introduce polymer into the internal pores of the 13X zeolites. The approach is similar to that used by Wu and Bein [150-152] to form molecular-scale wires of polyaniline or carbon within nanometer-sized channels. 

The linear polystyrene PS or PEA chains could be partially or wholly removed from the PIPNs by extraction with suitable solvents. On the other hand, no significant weight loss was found on extensive solvent extraction of the IPNs. Characterization of these materials provided substantial confirmation that at least some of the polymer grew within the internal pores of the zeolite [62, 140], The major results supportive of this conclusion were  

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The template-assisted synthetic strategies outlined above produce micro- or mesoporous stmetures in which amorphous or crystalline polymers can form around the organic template ligands (174). Another approach is the use of restricted spaces (eg, pores of membranes, cavities in zeolites, etc.) which direct the formation of functional nanomaterials within thek cavities, resulting in the production of ultrasmaU particles (or dots) and one-dimensional stmetures (or wkes) (178). For example, in the case of polypyrrole and poly(3-methylthiophene), a solution of monomer is separated from a ferric salt polymerization agent by a Nucleopore membrane (linear cylindrical pores with diameter as small as 30 nm) (179—181). Nascent polymer chains adsorb on the pore walls, yielding a thin polymer film which thickens with time to eventually yield a completely filled pore. De-encapsulation by dissolving the membrane in yields wkes wherein the polymer chains in the narrowest fibrils are preferentially oriented parallel to the cjlinder axes of the fibrils. 

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