Bioinspired Micro Glue Threads Fabricated by Liquid Bridge-to-Solidification as an Effective Sensing Platform.

Spiders synthesize their web using a liquid bridge-to-solidification mechanism at the end of their glands. Inspired by this process, in this work, we fabricated micro-glue threads (μGTs, polymer microwires) by a simple "pinch and spread" process using just two fingertips. The μGTs exhibited excellent tensile strength (∼50 GPa), comparable to those of spider silk and biological fibers. The chemical, physical, and mechanical properties of the μGTs were investigated, and it was confirmed that the thickness of the μGTs could be controlled by ethanol treatment in varying concentrations. Moreover, electrically conductive μGTs were easily fabricated by simply mixing them with various nanomaterials such as gold nanoparticles, zinc oxide nanowires, and reduced graphene oxide (rGO). Interestingly, the conductive μGTs, fabricated using rGO, exhibited remarkable electrical conductivity (0.45 μS) compared to those fabricated using other materials. The conductive μGTs are applicable not only to NO2 gas sensing but also as electrical fuselike materials that melt when the humidity increases. Collectively, the results present μGTs as cost-effective, simple, and versatile materials, which enables their application in a variety of sensors.