Recently, there has been exceptional growth in research related to the development of flexible sensors for health analysis. pH measurements can be done non-invasively and continuously, making such sensors an excellent choice for monitoring different stages of wound healing. Here, we report pH functionality of a polyaniline/graphite (PANI/G) composite in a fully-printed potentiometric pH sensor and the effect of graphite loading on sensor functionality. PANI/G composites in different ratios were aerosol-jet printed on Ag/AgCl with and without a graphite layer as the working electrode in a two-electrode potentiometric sensor on a flexible substrate. The role of the graphite layer on the working electrode in the functionality of the sensor has been investigated. The PANI/G composites were prepared by a solution processing method using a graphite paste and polyaniline emeraldine salt powder. Samples were characterized by X-ray diffraction, scanning electro microscopy, and Fourier transform infrared analysis to investigate the relations between the physical and chemical relations and the performance of the sensors. The sensors were tested in the pH range from 3 to 10, exhibiting a linear, stable and near-Nernstian sensitivity of 53 mV/pH and a response time of 15 s.

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Activated carbon from walnut shell is studied for methane storage in this research. The samples are synthesized by zinc chloride and phosphoric acid as activating agents. The e ect of physical activation, after chemical activation steps, on the nal structure of the samples and their total methane storage is examined. The results show that physical activation has an improving e ect on the total capacity of the samples activated by phosphoric acid; however, it has the opposite e ect on the capacity of the samples activated by zinc chloride. The experimental data show that the best capacity is obtained at impregnation ratios of 0.7 and 1.2 in the case of phosphoric acid and zinc chloride activated samples, respectively. The best sample is the one activated by phosphoric acid with an impregnation ratio of 0.7 and, subsequently, physically activated by carbon dioxide. It has a BET surface area of 1479 m 2 /g, an average pore diameter of 4.2 nm, the total pore volume of 0.84 cm 3 /g, and the methane adsorption capacity of 159 cm 3 /g. The sample shows high stability during successive adsorption/desorption cycles experiment.