High-sensitivity strain gauges based on single wires of close-packed 14 nm colloidal gold nanoparticles are obtained by a novel variant of convective self-assembly (CSA). This CSA mode named stop-and-go CSA enables the fabrication of nanoparticle wires only a few micrometers wide, separated by distances that can be easily tuned over tens to hundreds of micrometers. Nanoparticle wires are obtained in a single step by direct deposition of nanoparticles from suspensions onto flexible polyethylene terephthalate films, without any lithographic prepatterning. When connected between two electrodes, such single nanoparticle wires function as miniature resistive strain gauges. The high sensitivity, repeatability, and robustness demonstrated by these single-wire strain gauges make them extremely promising for integration into micro-electromechanical systems or for high-resolution strain mapping.

High-sensitivity resistive strain gauges based on electron tunneling in assemblies of gold colloidal nanoparticles are fabricated and characterized. The active area of these strain gauges consists in well-defined arrays of parallel, few micrometer wide wires of close-packed 18 nm gold nanoparticles. These nanoparticle wires are obtained by convective self-assembly (CSA) on flexible polyethylene terephtalate substrates, without any lithographic prepatterning. The fine control over the thickness and the width of the nanoparticle wires through the substrate temperature and the meniscus speed during the CSA process allows demonstrating the strong impact of the dimensionality (2D or 3D) of the nanoparticle assembly on the strain gauge sensitivity. Wires made of a single monolayer of nanoparticles turn out to give strain gauges about three times more sensitive than those made of multilayers. This work shows that the simplicity and versatility of convective self-assembly over other alternative methods make this technique very suitable for the reliable and low-cost fabrication of miniaturized, highly sensitive nanoparticle-based strain gauges.