Large effect of titanium precursor on surface reactivity and mechanical strength of electrospun nanofibers coated with TiO2 by atomic layer deposition

Abstract

Encapsulating and functionalizing polymer nanofibers can improve the polymers chemical resistance and surface reactivity, enabling new applications including biosensing, flexible electronics, gas filtration, and chemical separations. Polymer fiber functionalization typically involves energy intensive wet chemical treatments and/or plasma exposure. Recent results show low temperature atomic layer deposition (ALD) to be a viable means to coat nanofibers with uniform and conformal inorganic and hybrid organic–inorganic layers. For this article, the authors describe how the mechanical properties of nylon-6 nanofibers are affected by ALD coatings of TiO2 and other metal oxides. They find that the stress–strain behavior of nylon-6 nanofibers depends strongly on the specific precursor chemistry used in the coating process. For ALD TiO2 coatings, titanium tetrachloride tended to embrittle the fibers, whereas titanium isopropoxide had a more subtle effect. Physical characterization shows that the TiCl4 diffused into the nylon-6 and reacted subsurface, whereas the titanium isopropoxide tended to react on the surface producing a more abrupt organic/inorganic interface. Results show that precursor choice is an important factor when designing thin film coating processes on polymeric substrates.

Conductivity and touch-sensor application for atomic layer deposition ZnO and Al:ZnO on nylon nonwoven fiber mats

“…11,[26][27][28] For some applications, conductive fiber mats may have a mechanical advantage over planar films because fibers offer a multiplicity of parallel conduction pathways, so that many fractures are needed before failure. Recent reports show ALD coatings can enhance or degrade mechanical performance, depending on properties of the substrate and the coating.…”

Surface Decoration of Pt Nanoparticles via ALD with TiO2 Protective Layer on Polymeric Nanofibers as Flexible and Reusable Heterogeneous Nanocatalysts

“…On the other hand, the stability of the flexible polymeric support in the form of nanofibrous web would be the crucial issue during the decoration of metal NP in different ALD reactive atmospheres. By placing the protective layer through ALD on nanostructures and polymeric fibers could improvise its stability and durability under different reactive atmospheres and different reaction temperatures 21 , 22 . In one of the related study, by ALD process, coating of a passivation AlZnO:Al 2 O 3 layer over the electrospun Cu nanofibers has enhanced its stability against the oxidation and corrosion 23 .…”

Delayed Dissolution and Small Molecule Release from Atomic Layer Deposition Coated Electrospun Nanofibers

“…To date, the use of ALD on nanofibers has focused on fabrication of hollow nanostructures, such as nanotubes, which are synthesized using polymer nanofibers as templates . But ALD has also been used to alter physical properties of nanofibers including mat strength, chemical resistance, and photocatalytic activity . Our goal is to exploit this knowledge and demonstrate that ALD treatment can also be utilized to modify the dissolution properties of nanofiber mats without significantly altering the bulk polymer chemistry.…”