The fabrication of three-dimensional (3D) polypyrrole conductive tracks through the porous structure of paper is demonstrated by the first time. We combined paper microfluidics and gas-phase pyrrole monomers to chemically synthesize polypyrrole-conducting channels embedded in-between the cellulose fibers. By using this method, foldable conductive structures can be created across the whole paper structure, allowing the electrical connection between both sides of the substrate. As a proof of concept, top-channel-top (TCT) and top-channel-bottom (TCB) conductive interconnections as well as all-organic paper-based touch buttons are demonstrated.

Mass spectrometry was used to monitor neutral chemical species from sugar cane bagasse that could volatilize during the bagasse ozonation process. Lignin fragments and some radicals liberated by direct ozone reaction with the biomass structure were detected. Ozone density was monitored during the ozonation by optical absorption spectroscopy. The optical results indicated that the ozone interaction with the bagasse material was better for bagasse particle sizes less than or equal to 0.5 mm. Both techniques have shown that the best condition for the ozone diffusion in the bagasse was at 50% of its moisture content. In addition, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to analyze the lignin bond disruptions and morphology changes of the bagasse surface that occurred due to the ozonolysis reactions as well. Appropriate chemical characterization of the lignin content in bagasse before and after its ozonation was also carried out.

We use a combined process of Ga-assisted deoxidation and local droplet etching to fabricate unstrained mesoscopic GaAs/AlGaAs structures exhibiting a high shape anisotropy with a length up to 1.2 μm and a width of 150 nm. We demonstrate good controllability over size and morphology of the mesoscopic structures by tuning the growth parameters. Our growth method yields structures, which are coupled to a surrounding quantum well and present unique optical emission features. Microscopic and optical analysis of single structures allows us to demonstrate that single structure emission originates from two different confinement regions, which are spectrally separated and show sharp excitonic lines. Photoluminescence is detected up to room temperature making the structures the ideal candidates for strain-free light emitting/detecting devices.