Composite films of natural clay nanotubes with cellulose and chitosan

Composite films based on cellulose, chitosan and halloysite clay nanotubes were prepared using a solution casting method, which allowed for a uniform distribution of nanotubes within the material and provided control over the morphology of the composite. The mechanical performance of these bio nanocomposites is influenced by humidity and the nanotubes showed a plasticisation effect on the polymeric matrix. The composites of chitosan and halloysite nanotubes (HNTs), with modified hydrophobic inner lumens, resulted in a technique for controlled and sustainable surface cleaning. Lignocellulose wood microfibres modified with HNTs were also produced by a layer-by-layer assembly. The obtained material represents a composite well suited for making paper sheets for biomedical applications, where enhanced porosity can be crucial. Toxicity tests carried out on biopolymer–halloysite composites showed that these nanocomposites are safe for cell cultures up to 0·5 mg/mL of free clay nanotubes.