Halloysite nanotubes (HNTs) are natural tubular materials, which show a number of attractive advantages such as the unique micro-spatial structure, large length-diameter ratio, high lumen volume, nontoxicity and widespread. The development of HNTs-based polymer composites expanded their applications in the fields of energy, catalysis, biomedicine, environmental protection and many others. This review will briefly summarize the purification, characterization and modification methods upon HNTs, in which the preparation and application of the HNTs-based polymer composites are emphasized. This paper may be beneficial for the development of novel strategies for the preparation of new libraries of HNTs-based polymer composites and the exploration of their applications.

Developing X-ray scintillators that are water-dispersible, compatible with polymeric matrices, and processable to flexible substrates is an important challenge. Herein, Tb³⁺-doped Na₅Lu₉F₃₂ is introduced as an X-ray scintillating material with steady-state X-ray light yields of 15,800 photons MeV⁻¹, which is generated as nanocrystals on halloysite nanotubes. The obtained product exhibits good water-dispersibility and highly sensitive luminescence to X-rays. It is deposited onto a polyurethane foam to afford a composite foam material with dose-dependent radioluminescence. Moreover, the product is dispersed into polymer matrixes in aqueous solution to prepare rigid or flexible scintillator screen for X-ray imaging. As a third example, it is incorporated multilayer hydrogels for information camouflage and multilevel encryption. Encrypted information can be recognized only by X-ray irradiation, while the false information is read out under UV light. Altogether, we demonstrate that the water-dispersible scintillators are highly promising for aqueous processing of radioluminescent, X-ray imaging, and information encrypting materials.