Adding Multifunctionality to Textiles: Synthesis, Characterization, and Application of ZnO Nanostructured Coatings on Fibrous Substrates

The incorporation of inorganic nanostructured coatings on textile materials has attracted considerable interest in recent years given the tremendous possibilities of adding multifunctionality to fabrics such as antimicrobial activity, UV protection, self-cleaning properties, anti-counterfeiting, energy harvesting and sensing capabilities.  Among the different choices of inorganic materials for ‘smart’ textile applications, quasi-one dimensional zinc oxide (ZnO) nanostructures are a top alternative owing to their unique optical, electrical, mechanical, and physical properties.  Conventional methods to synthesize ZnO nanostructures include: pulse laser deposition, sputtering techniques, thermal evaporation, and chemical vapor deposition.  However, these methods are not ideal for textiles due to their processing conditions, which would destroy the mechanical properties (i.e., feel and strength) of many fibrous materials.  Here we present a convenient, aqueous-based, low temperature process to synthesize ZnO nanostructures on cotton and nylon fibrous substrates.  High surface coverage and conformal growth of ZnO nanoneedles – with defined diameters and morphologies – was achieved via specific physical/chemical interactions of the ZnO precursor species with functional groups present on the fiber surface.  Surface chemical functionalization strategies were employed to both impart super hydro/oleophobic properties to the ZnO-coated cotton substrates and for the layer-by-layer synthesis of metal/metal oxide junctions on ZnO-coated silver plated nylon threads.