Fabrication of natural cellulose substance derived hierarchical polymeric materials

Hierarchical porous metal oxide/polymer hybrid and polymer materials were fabricated by replication of natural cellulosic substances and successive removal of the template cellulose components using a solution dissolving method under mild conditions. Commercial filter paper was employed as the template, metal oxide/polymer (titania/polyvinyl alcohol) composite ultrathin films were deposited by layer-by-layer assembly to replicate its structures with nanometer precisions, and the cellulose components were thereafter removed by treating with sodium hydroxide/urea solution. The resulting hierarchical porous titania/PVA composite sheets possessed the initial structures and morphologies of the template cellulosic substance, and also inherited the corresponding physical properties such as flexibility and swelling property in various solvents. Pure hierarchical PVA material was successively obtained by removing the titania component from the titania/PVA hybrid sheets with acidic treatment. The current research breaks the limitation caused by calcination employed in general template syntheses to burn off the template component, opening a pathway for the design and preparation of bio-inspired polymeric and organic materials.