ABSTRACT
An aerosol jet printing (AJP) process for depositing ruthenium dioxide (RuO2) as a promising material for pH sensing is reported. Graphene oxide (GO) with a large surface area was used for the in situ sol-gel deposition of RuO2 nanoparticles on its surface. The cosolvent ratio and solid loading of the solution are adjusted to form a printable and stable ink. The monodispersed aerosol was atomized on the surface of the screen-printed carbon electrode in order to develop an integrated pH sensor. The RuO2-GO pH sensor demonstrates excellent performance, with a rapid response time of less than 5 s and high sensitivity in the pH range of 4-10. Compared to traditional carbon electrodes, the RuO2-GO sensor shows up to four times higher sensitivity. The increased sensitivity is a result of the consistent attachment of small-crystallized RuO2 nanoparticles onto the surface of GO sheets, leading to a synergistic effect. Thanks to the AJP method as a facile and cost-effective integration technique, the fabricated electrodes can serve as an alternative to traditional rigid pH electrodes for accurate pH measurement.
ABSTRACT
Tunable mesoporosity and nanoporosity of stimuli pH-responsive (N-vinyl imidazole-ran-acryloylmorpholine) hydrogels studied in terms of %swelling at various ionic strength, pH, temperature, and crosslinker concentration values were investigated. Hydrogel properties including diffusional exponent, number of links between two crosslinks, rms end-to-end distance and mesh size of gels were evaluated. The structural sequence of the scaffolds was tested and verified using Kelen-Tudos technique, and Alfrey-Price relationship. Hydrogels were characterized using FTIR, thermogravimetric analysis, differential scanning calorimetry, and freeze-dried Scanning electron micrographs techniques. The reversible pH responsiveness and possible mesoporous and nanoporous (i.e., 0.88-4.03 nm) structures suggest their suitable candidate in membrane technology and/or is an adequate drug delivery vehicle in drug delivery systems.
