Novel Optimized & Versatile Surface Chemical Engineering of Mechanically Robust Inorganic Tungsten Disulfide (WS₂) Nanotubes (f-INT-WS₂) - Potentiality for Nanoscale CNTs Replacement

An innovative method of chemically versatile surface functionalization (polycarboxylation – sidewall polyCOOH shell) of tungsten disulfide (WS₂) multi-walled inorganic nanotubes (INTs-WS₂) has been successfully developed based on N-relating strongly electrophilic species (imminium salt chemistry). This newly developed nanotube sidewall multi-parametric polyCOOH functionalization has been also globally optimized (Design of Experiments statistical method, DoE optimization). Thus, it enabled an extremely wide chemical versatile range of various 2^nd step surface engineering/derivatization reactions (covalent attachment of proteins, peptides, small ligands, etc…). Indeed and for example, it provided various attractive covalent INTs-WS₂ chemical surface modifications (polyNH₂, polyOH, polySH as 1^st series of shells examples) via (i) polyCOOH chemical activation (EDC, CDI) and (ii) 2^nd step nucleophilic substitutions by short ω-aminated ligands H₂N-linker-X, X outer surface functionality). Resulting fully characterized functional INTs-WS₂ (f-INTs-WS₂) nanotubes have a quite wide potential for use as novel functional nanoscale inorganic fillers toward new mechanically strengthened composite polymeric matrices/coatings. These novel functional nanoma-terials/”nanoscale fillers” have been also shown to be non-toxic in preliminary toxicity studies, which opens a wide R&D route/progress for corresponding appropriate end-user applications as CNTs replacing non-toxic inorganic nanofillers.