Multipurpose nanocomposite resist for free-standing transparent conductive thin films

Abstract

Nanocomposites formed by silver nanowires (AgNWs) embedded in a polymer matrix are a convenient way to deposit thin films with electrical conductance and high transparency on different substrates. Nanocomposite resists containing AgNWs in a poly(methyl methacrylate) solution can be effectively used to produce conductive coatings in a straightforward manner. Here, we show that by adding a sacrificial layer of polyvinylpyrrolidone on a glass substrate, prior to the nanocomposite resist, it is possible to obtain large-area free-standing films of about 450 nm with electrical conductance and high transparency. The films can be transferred to different surfaces and materials including non-flat substrates. The formation of conductive stacks by piling two layers was also demonstrated. The optical, electrical, and structural properties of these free-standing films were studied obtaining films with transmittance T(%) = 78% at 550 nm, sheet resistance Rs = (670 ± 40) Ω sq−1 and surface roughness Ra = (50 ± 10) nm. We studied the strain resistance behavior of films transferred to polyethylene terephthalate sheets under bending tests finding a sensitivity of (0.51 ± 0.01) Ω deg−1 and a gradual increase in the resistance during cycling. In addition, thin flexible supports can be added by covering the nanocomposite film with polydimethylsiloxane (PDMS) prior to its release, enhancing the mechanical robustness and improving the manipulation of the films.